The Shutter Thumb Rester from Brando is a add on for your camera that provides a resting place for your thumb. The idea is that it allows for a more relaxed/natural grip on your camera, so that it will prevent shaking. The accessory is made of a “high quality material”… Not sure what the actual material is. It looks metal from the images. It comes in two sizes and fits in the hotshoe of your camera. The Shutter Thumb Rester is $29.00.