The Trigrest for Quark Nomic Ergo Ice Tool by Petzl. The TRIGREST hand rest is adjustable in height, without tools, on the shaft or the handle.
It has two support positions: a brace for hand switching in the high position, and a brace for the index in the low position. The latter increases grip strength for leashless climbing and improves planting precision.
The Trigrest may also be used in a fixed position, without the index support.