Petzl B17ALN Assisted Braking Belay Device for Single Ropes 8.5-11mm

Unlike conventional tube-style devices, the Petzl B17ALN integrates an assisted braking cam that locks the rope under sudden load, while still allowing smooth, controlled lowering with an ergonomic handle. Two selectable modes—top-roping and lead climbing—let you tailor the friction response to the situation, making it a versatile choice for both gym sessions and multi-pitch routes.

Highlights

• Assisted braking for single ropes from 8.5 to 11 mm (optimized 8.9–10.5 mm)
• Two belay modes: top-roping and lead climbing, easily selectable
• Anti-panic function in both modes stops an uncontrolled descent if the handle is pulled too hard
• Ergonomic reinforced nylon handle ensures comfortable, precise lowering
• Durable construction: aluminum side plates, stainless steel cam and friction plate
• Engraved rope installation diagram for quick, mistake-free threading
• Certified to CE EN 15151-1 and UIAA standards

In daily use

Whether you are belaying a projecting partner on a steep sport climb or managing a top-rope session at the local crag, the B17ALN delivers consistent braking with minimal effort. The cam engages automatically when the rope accelerates, giving you a reassuring margin of safety. When lowering, the handle allows progressive release; if you pull too far, the anti-panic mechanism re-engages the brake, preventing a fall. The device works with all dynamic single ropes in the specified diameter range and pairs with most locking carabiners. Its compact size and moderate weight make it easy to carry on long approaches.

Full specifications

• Rope compatibility: Single ropes 8.5–11 mm (optimized 8.9–10.5 mm)
• Belay type: Assisted braking
• Belay modes: Top-roping and lead climbing (selectable)
• Anti-panic function: Yes (in both modes)
• Descent control: Ergonomic handle
• Frame material: Aluminum side plates
• Cam material: Stainless steel
• Friction plate material: Stainless steel
• Handle material: Reinforced nylon
• Certifications: CE EN 15151-1, UIAA
• Rope installation diagram: Engraved on device
• Intended use: Indoor and outdoor climbing
• Compatibility: All dynamic single ropes and most locking carabiners

Final note

The Petzl B17ALN offers a reassuring margin of safety with its cam-assisted braking and anti-panic function, making it a reliable choice for climbers who demand both performance and peace of mind.