How to Use a Belay Device? | Keep the Brake Hand On

Belaying takes practice, and every part of it rests on that single habit. It covers feeding slack to a leader, locking off during a fall, and lowering a climber, whether the device is a simple tubular model or a cam-assisted one.

Belay devices split into two families — cam-assisted and tubular — and both demand the same brake-hand technique. Here’s what climbers actually use:

Belay Device Basics: Attach, Thread, Check

Every device mounts the same way: clipped to your harness belay loop with a locking carabiner, with the rope threaded per the engraved diagram. Get these three steps right and the rest gets simpler.

1. Attach the device to the harness belay loop. Petzl’s GRIGRI and REVERSO instructions both require a locking carabiner here, kept clipped for the whole climb.
2. Thread the rope per the engraved diagram. Petzl tells users to follow the marking and check orientation carefully — guessing the rope path is a documented cause of accidents.
3. Run a function check. Load the rope before the climber leaves the ground and confirm the braking action engages; you should feel the device grab.

Once your climber starts, leave the setup alone. USA Climbing’s handbook is explicit: never unload or unthread the rope after the climb has begun.

How Do You Feed Slack, Catch a Fall, and Lower?

The same hand pattern covers every stage: one hand stays on the brake-side rope at all times, the other moves rope through the device.

• Feeding slack: push the brake-side rope toward the device with your brake hand while the other hand pulls rope through. Smooth motion keeps the leader from feeling drag.
• Taking up slack: pull the climber-side rope, then pull the brake-side rope through until you’re back in the locked position.
• Catching a fall: your brake hand locks down; on cam-assisted models the mechanism grabs too. That cam is a backup, not a replacement — the brake hand does the real work.
• Lowering: work the release handle gradually while feathering the brake rope. Keep the brake hand on for the entire descent.

Practice each motion on the ground first, because muscle memory keeps the brake hand down when you’re tired. With a tubular device, the brake hand grips the rope below the device — speed control comes from grip alone. If the rope runs faster than you want during a lower, pull the brake rope harder, and keep that hand on it no matter what.

The same sequence applies across Petzl’s GRIGRI, REVERSO, and VERSO devices, as spelled out in Petzl’s universal belay technique.

Common Mistakes and the Big Safety Rules

Nearly every belay-related accident traces back to one of two errors: the brake hand lets go, or the rope is threaded wrong. Both are preventable.

• Letting go of the brake-side rope is prohibited. Petzl’s guidance is unambiguous — the brake hand never leaves the rope, at any point.
• Wrong threading is a documented hazard. Follow the engraved diagram, double-check orientation, and test the device before loading it.
• Assisted braking doesn’t replace technique. USA Climbing requires your device meet manufacturer specs, stay in good condition, and be familiar to you. The cam is a helper, never a babysitter.
• Double-rope devices have their own rules. The Metolius BRD takes one rope per slot, both free of twists, with the rope from the climber or anchor on the lever side.

Petzl’s videos extend the same brake-hand rule to the NEOX. If you’re still choosing designs, our tested roundup of the best climbing belay devices compares top models side by side. Whichever you pick, the technique stays the same: brake hand on, always.