How To Belay: Using Assisted Locking Belay Devices

How you belay with an assisted braking belay device depends on which kind you have in your hands. They do not all work the same way, and if you learned how to belay on one device, the next one in the gym rental bin might behave differently.

In this guide we will show you how to tell which type of assisted locking belay device you are holding, and how to belay with each one. Before we get into it, one thing matters more than anything you will read here: get proper hands-on instruction from a qualified instructor or an experienced belayer, and read the manual that came with your device. An article can point you in the right direction, but it cannot watch your hands. Your partner is trusting you with their safety, so treat every step like it counts. If you are still new to any of this, start with our Belaying 101 guide and then come back.

What Is an Assisted Braking Belay Device?

An assisted braking belay device is a tool climbers use to keep the climber safe and control the speed of the rope moving through the device. Compared to an ATC, an assisted braking belay device also helps stop an accidental fall if the belayer is not paying attention. It locks the rope in place and keeps it from moving through the device until the belayer intentionally lowers the climber. If you are weighing whether one is right for you, we broke that down in should you upgrade to an assisted-braking belay device.

There are two families of assisted braking belay devices: semi-assisted and auto-locking. With semi-assisted devices, the way they work is the same across the different brands.

With auto-locking devices, there are two main types and they work differently. The most common is the one-direction camming auto-locking device, and the second is the bi-directional camming auto-locking device.

3 Types of Assisted Braking Belay Devices

There are three main types of assisted braking belay devices on the market today: the one-direction camming auto-locking belay device (the oldest of the locking devices), the semi-assisted locking devices, and the newer bi-directional camming auto-locking belay device.

One-Direction Cam Auto-Locking Belay Device

The difference between the auto-locking and the semi-assisted devices is that the auto-locking device pinches the rope with a camming mechanism inside the device, and it works independently from the carabiner.

There are two types of auto-locking belay devices. The one-direction cam is the oldest locking belay mechanism brought to market. It came out with the first Grigri in 1991 and has been used by many brands since.

Popular one-direction cam auto-locking devices:

• Petzl Grigri
• Birdie
• Tango Vergo 
• Camp Matik 
• Madrock Lifeguard 

They are called one-direction cam because there is one cam in the device (a metal knob) that moves in one direction to lock the rope in place.

The one-direction cam auto-locking belay devices use the weight of the rope attached to the climber to control how the cam sits. When the climber falls, the rope jars the camming device forward, which pinches the rope and keeps it from moving through the device. If you climb on a Grigri, it is also worth learning how to belay with a Grigri for top rope climbing before you use it for real.

Bi-Direction Cam Auto-Locking Belay Devices

There is only one bi-direction cam auto-locking belay device on the market right now, and that is the Wild Country Revo.

What sets the Revo apart from the one-direction cam auto-locking device is that the camming mechanism works in two directions. That lets the belayer load the rope into the device in either direction, and belay left or right-handed.

For the Revo specifically, the central camming mechanism is only able to spin up to about 4 meters per second. When the mechanism goes past that speed (like when a climber falls), the device engages the cam and stops the rope from moving through it, locking the rope in place.

The rope can move again once the belayer reengages the device, and from there the belayer controls the climber’s descent.

Semi-Assisted Locking Belay Devices

These belay devices lock the rope if the climber falls, so the rope does not run through the device and cause a ground fall. On the market today there are three popular devices that count as semi-assisted locking belay devices.

Other popular semi-assisted locking devices:

1. Mammut Smart and Smart 2.0
2. Edelrid Jul and Jul 2
3. Black Diamond Pilot

All of these devices work the same way. The shape of the belay device has an extra lip or extrusion that, depending on the direction the device is sitting, can block the rope from running through.

If the belay device is in an upward or neutral position, the rope runs through the device freely.

If the device tips to a forward position, where the top of the device faces forward (caused by the climber falling and forcing the device forward), the rope gets locked between the carabiner and the belay device.

How To Belay With a One-Direction Cam Auto-Locking Belay Device

The general use of a one-direction cam auto-locking device is the same across all brands. That said, always read the device manual first to make sure you are using it safely.

How to load rope into the device

1. Slide the device open.
2. Place the rope around the cam mechanism with the climber side of the rope closest to the carabiner loop and the feeding/brake side away from the carabiner loop. All of the mainstream brands stamp images on the device to help. Usually there is a climber icon, which shows that the rope going to the climber should sit on that side, and an icon of a hand holding rope, which shows which side the brake rope should come from.
3. Slide the device closed.
4. Attach the device with a carabiner through the carabiner loop on the belay device and through the belay loop on your harness.

Loading the rope wrong will make the belay device useless and unsafe, so double-check it every time.

How to feed out rope through the device

There are two main ways to feed rope out through the device.

The first way works well while the climber is heading up the wall. You pull the rope up with your left hand while your right hand brings the rope closer to the device, just like an ATC. Keep in mind that some auto-locking belay devices, like the Grigri, are known to lock up when you feed slack out too fast.

If you need to feed slack quickly and the device keeps locking up, use the second way.

Remember: keep a hand on the brake rope at all times.

1. Keep your right-hand pinky, ring finger, and middle finger on the brake rope, and hold the device up with your pointer finger on the lip of the device.
2. Place your right-hand thumb on the back side of the lever and press down.
3. While your thumb presses down, quickly pull the rope through the device with your left hand until you have the slack you need.
4. Do NOT take your hand off the brake rope.

How to take in the rope through the device

This one is simple and very close to how you take in with an ATC.

1. With your left hand, pull the rope down and toward the device.
2. Pull the rope through the device with your right hand.
3. Place your left hand on the outside of your right hand onto the rope.
4. Slide your right hand up toward the belay device.
5. Repeat steps 1 to 4 as needed.

How to lower a climber 

All of the one-direction cam auto-locking models have a similar build for lowering climbers.

1. Do not take your hand off the brake rope.
2. Pull back the lever on the side of the belay device until the rope starts sliding through the device.
3. To speed the rope up, move the lever back slightly more.
4. To slow the rope down, move the lever slightly forward.
5. Adjust to the speed you want.

How To Belay With a Bi-Direction Auto-Locking Belay Device

Since there is only one bi-direction auto-locking belay device on the market today, these are specific directions for using the Wild Country Revo.

How to load rope into the Revo

1. Open the Revo using the black locking lever on the side plate.
2. Feed the rope around the orange wheel (in any direction, clockwise or counterclockwise) until both ends of the rope come out the top of the device.
3. Close the Revo and listen for an audible click so you know it is securely closed.
4. Orient the device so the brake side of the rope is away from the belayer.
5. Attach a locking carabiner through the bottom of the Revo and through the belay loop on your harness.

How to feed out rope through the device

Feeding rope out with the Revo is the same as an ATC.

1. Remember: keep your brake hand on the brake side of the rope.
2. With your top hand (not your brake hand), pull rope through the device up and away from you.

How to take in rope/slack through the device

This is the same as how you would take in with an ATC.

1. With your left hand, pull the rope down and toward the device.
2. Pull the rope through the device with your right hand.
3. Place your left hand on the outside of your right hand onto the rope.
4. Slide your right hand up toward the belay device.
5. Repeat steps 1 to 4 as needed.

How to catch a falling climber

The Revo will catch a climber if the belayer is negligent, but unlike the one-direction cam auto-locking device, catching a climber is meant to stay in the belayer’s control.

The Revo is built so you still treat it like an ATC, so this works the same as an ATC.

1. Pull the brake side of the rope down and across your body, against the Revo.
2. The fall gets caught just like with an ATC.

How to lower a climber

Lowering a climber with the Revo is very different from the one-direction cam auto-locking devices. There are two scenarios that change how you lower:

Unlocking with the tube up:

1. Hold the brake side of the rope with both hands.
2. Pull the rope down directly against the tube, which unlocks the rope.
3. Slowly let the rope in your brake hands slide through the device.

Unlocking with the tube down:

1. Hold the brake side of the rope with one hand and the climber side of the rope with the other hand.
2. Pull the brake side of the rope away from your body and through the Revo until the rope unlocks.
3. Slowly let the rope in your brake hand slide through the device.

How To Belay With a Semi-Assisted Locking Belay Device

Semi-assisted locking belay devices all work the same way, but the Edelrid Jul and Jul 2 unlock differently, so the lowering directions below reflect that.

How to load rope into the device

Loading rope into a semi-assisted locking belay device is the same as an ATC.

1. Take a bight of the rope (a folded piece of the rope).
2. Orient the rope so the brake side points away from the belayer and the climber side sits closest to the belayer.
3. Orient the belay device so the side with the lip or protrusion points away from the belayer.
4. Push the folded end of the rope into the device from the top.
5. Lock your carabiner around the device, the rope, and the belay loop on your harness.

How to feed out rope through the device

This is the same for all the devices on the market, and it is the same as an ATC.

1. Remember: keep your brake hand on the brake side of the rope.
2. With your top hand, pull the rope through the device while your brake hand pushes rope toward the belay device from the brake side.

How to take in rope/slack through the device

This is the same for all devices on the market, and it is the same as an ATC.

1. Remember: keep your brake hand on the brake side of the rope.
2. With your top hand, pull the rope down and toward the device.
3. Pull the rope through the device with your brake hand.
4. Place your top hand on the outside of your brake hand onto the brake side of the rope.
5. Slide your brake hand up toward the belay device.
6. Repeat steps 1 to 5 as needed.

How to lower a climber

This is where the Edelrid Jul and Jul 2 differ from the other popular semi-assisted braking devices.

For the Edelrid devices, you attach a carabiner to the back of the belay device and use that carabiner as a handle. For the Mammut and Black Diamond devices, you use the device itself as the handle.

1. Tilt the belay device backward to bring it into a more upright orientation.
2. If needed, also raise the belay device up and away from the carabiner.
3. To speed the rope up, raise the belay device higher and more upright.
4. To slow the rope down, move the device lower, toward the carabiner.

One more time, because it is worth it: keep your brake hand on the rope through every one of these steps, and if any part of this feels unfamiliar, get a qualified instructor to check your setup in person before you put a climber on the other end. Want to keep sharpening the rest of your climbing between sessions? The free Send Edition newsletter sends one short drill a week, about 15 minutes each, straight to your inbox. If you belay on a Grigri, it is also worth reading how to clean your Grigri so the cam keeps working the way it should.

Frequently asked questions

What is the difference between an assisted braking belay device and an ATC?

An ATC relies entirely on your brake hand to catch a fall. An assisted braking belay device adds a mechanism that helps stop the rope if the climber falls, either a cam that pinches the rope (auto-locking) or a lip in the device that pinches the rope against the carabiner (semi-assisted). It is a backup, not a replacement, so you still keep your brake hand on the rope at all times.

Can I let go of the brake rope with an assisted braking device?

No. Every device covered here still needs your brake hand on the brake side of the rope at all times. The assist helps catch a fall if you are not paying attention, but it is not designed to be hands-free, and treating it that way is how accidents happen.

How many types of assisted braking belay devices are there?

Three main types: the one-direction cam auto-locking device (like the Petzl Grigri), the bi-direction cam auto-locking device (the Wild Country Revo), and semi-assisted locking devices (like the Mammut Smart, Edelrid Jul, and Black Diamond Pilot). Loading and lowering differ between them, so learn the one you are actually using.

How do I know I loaded the device correctly?

Check the icons stamped on the device. Most brands mark a climber icon for the climber side of the rope and a hand icon for the brake side. Load the rope to match, close the device, clip your locking carabiner through the device and your belay loop, and do a partner check before anyone leaves the ground. Loading it wrong makes the device unsafe.

Is this article enough to learn to belay?

No, and please do not treat it as your only source. Use it to understand how the different devices work, then get hands-on instruction from a qualified instructor or an experienced belayer and read your device manual. Belaying is a skill you learn in person with someone watching your hands.

► Belaying 101: You Shouldn’t Climb Without Reading This

Sara Climbing Coach, Climbing Trainer, Writer

Sara is the founder of Send Edition, author of '77 Drills to Help You Climb Better,' the creator of 'Elevate Your Climbing: Training Planner and Tracker,' and climbing coach.

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