Petzl ASAP : Mobile fall arrester for rope.
For use on a safety rope.
* Stops a fall, slide or uncontrolled descent.
* Locks even if the device is grabbed during a fall.
* Works on vertical or angled rope.
* Moves along the rope without manual intervention (downwards and upwards).
* Easy to install and remove at any point on the rope.
more info on www.petzl.com/asap