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. However most climbers will carry Friends or other spring-loaded camming devices for these.
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. All the smaller sizes are particularly applicable for this sort of use, with sizes 2 and 2.5 being the right size for most quarry shot-holes.
All Tricams can also be used as standard nut.
They also come highly recommended by some climbers for winter use in iced up cracks.
Available singly or in a set of six from 0.125 - 2.