ACP Picatinny Fit Adjustable Cheek Rest Fully adjustable cheek rest. Designed to mount on the #CBS butt stock’s Picatinny rail. Adjustable for height with thumb knob (2.4cm range). By moving horizontally along the Picatinny rail, allows proper eye relief of scoped rifles. All can be easily fit to both left/right handed users. Compatible with our CBS buttstock.