A no moving parts camming device that cams well into horizontal breaks, where a good tug on the tape will seat it firmly into place.
This Evo version is also slightly wedge-shaped so that it can be placed as a standard nut in two planes and features new, stiffer sewing on the slings for easier one-handed placement and extraction. The wider section at the top of the head that creates the extra taper will also lend additional stability in cammed placements.
The real strength of Tricams is that, due to their narrow head width, they are often the only device that can be placed in round pockets that other camming devices will not fit in.
They also come highly recommended by some climbers for winter use in iced up cracks.