Petzl Large Sky Hook
A very useful part of any bolting kit, as it allows hands-free positioning while placing bolts, expecially for off-line rebelays and deviations.
Steel, with nylon - dyneema sling, weight 50g. It takes body weight plus, but isn't for rigging off! It may be used in progression while aid climbing, of course, if one is brave or impatient...