The Harken Ninja Foot Ascender is the only foot ascender which can be used on either foot, with a maximum working load of 1.5kN (330 lb) and rope compatibility up to 13 mm (1/2").

 

The housing is constructed from aluminium and the rope-holding dual cams are stainless steel making the ascender lightweight and durable. The Ninja is designed with springs that reduce rope drag meaning that there is a smoother and easier take off without having to counterweight the rope or reach down to pull the rope through the unit.

 

A transverse ribbed cam reduces damage to the rope and a dual cam system applies pressure to both sides of the rope simultaneously. This provides more thorough and even force than competitive designs whose cams act on just one side of the rope against a fixed wall on the other side.