Cheek pieces snap onto most standard M4-style collapsible stocks and provide comfortable and stable support proper eye alignment and consistent precision when using optics or iron sights. Set includes two models featuring different heights – the CP1 raises cheekweld 0.7" for EOTech and similar optics while the CP2 offers a 1.25" rise for iron sights. Quick easy installation and removal require no gunsmithing or tools. Each unit anchors into the stock's horizontal ribs and can be positioned along the length of the stock for optimal eye relief. Made of rugged fiberglass reinforced polymer to withstand harsh tactical conditions. Mfg: Command Arms Acc SPECS: Reinforced polymer black. Fits most M4-style collapsible stocks with horizontal ribs. Not compatible with Magpul stocks.