ISPO Award Winner 2025: Mammut Assist Belay Resistor

There’s this moment every climber knows: Your partner takes a fall, and you feel the sudden pull through the rope. Your body lifts off the ground, your heart jumps, and for a split second, you’re reminded how much trust climbing really takes. Anyone who’s ever belayed a much heavier partner knows how tough it can be. The pull isn’t just sudden: You’re yanked upward, maybe into the wall, maybe into your partner. It’s scary and dangerous. And it happens more often than we like to admit. That’s exactly where the Mammut Assist belay resistor comes in.

»We are very proud to introduce the Mammut Assist, a product that will make climbing more accessible for everyone, regardless of weight. By reducing the challenges of weight differences, it enhances both safety and enjoyment for climbers of all levels«, Magnus Raström, Senior Product Manager at Mammut explains. »And most importantly, it will helps maintain trust and harmony in belay partnerships, saving countless belay relationships.« 

The magic of the Mammut Assist lies in its patented cam construction. When not engaged, the rope glides freely through the device. Belaying feels natural and is smooth, intuitive, effortless. The mechanism stays fully open until it’s needed, meaning you barely notice it’s there. False activations are reduced to a minimum, while the device doesn’t interfere with your normal belaying rhythm. The system only changes in two situations: when a climber falls or when you’re lowering them down. Until then, it stays in standby, allowing fluid rope handling with the added bonus of intelligent safety.

When a fall happens, the Mammut Assist comes to life. The system is pulled upward, engaging the cam. The rope then curves around the cam and a steel insert, which increases friction. But here’s the clever part — the rope isn’t locked completely. Instead, it’s re-routed to create extra friction without blocking.  

This design makes all the difference: It allows for soft catches, meaning that falls feel more dynamic and gentle for the climber. You don’t get that abrupt, jarring stop but the mechanism allows more smoothness, comfort and safety on the wall. On top of that, the reduced friction and smoother engagement help extend the lifespan of your climbing rope.

The Mammut Assist also proves its worth in one of the most dangerous moments in climbing - falling directly into the first quickdraw. In this case, the device activates immediately. The cam engages, and additional friction is created through V-shaped slots at the bottom. The result? Instant braking power that can make the difference between a close call and a ground fall.  

It’s a clever safety feature designed for those early moments in a climb when you’re still close to the ground and risks are highest.

A weight difference in climbing doesn’t just make it uncomfortable but it can be dangerous. And it’s not a rare issue. Studies show that weight difference played a role in 60% of gym lead-climbing accidents. The general rule of thumb is that you should take precautions with a weight difference of as little as 5 to 10 kilograms.

The Mammut Assist adapts to your needs and offers two attachment options for additional flexibility:

• Standard mode: Attach it with a quickdraw to safely manage weight differences of up to 35 kg. 

• Boost mode: Use a locking carabiner instead, and it handles differences of up to 45 kg.

This means you can easily adjust how much assistance you need depending on who you’re climbing with - without changing your belay technique.

Guided by the principle that form follows function, Mammut designed this device to be intuitive, compact, and lightweight. It’s a tool that fits seamlessly into your setup without adding bulk or complexity. Despite its clever engineering, it’s simple to use and quick to set up.  

The construction is engineered for durability without any textile parts, built to perform reliably year after year. It’s made for the long haul, not just for one climbing season.

• Patented cam construction ensures smooth rope handling; activates only when needed
   
• Allows dynamic belaying
   
• Automatically releases when climber resumes after a fall
   
• Reduces ground-fall risk on first quickdraw
   
• Enables controlled lowering of heavier climbers