The ARC is a modular replacement ring cap for any Condition One Modular Mount. It allows the user to mount a myriad of accessories fore or aft on their C1 Mounts to include different variants of Laser Range Finder rails or 12 o’clock mounted Red Dot Optics. The C1 ARC allows the accessories to be connected or disconnected without removal of the ARC itself thus maintaining zero of your primary optic. 7075 T6 Aluminum, Mil Spec Type III Hardcoat Anodized. 1.8 ounces.