The 30mm Trijicon Accessory Ring Cap is designed to replace the front or rear cap sold with Q-LOC style mounts. Three mounting locations allow red dot or picatinny rail mounting plates to be attached at 12 o-clock or 45 positions. Designed to integrate with Trijicon Q-LOC and Slimline style variable power mounts, this lightweight cap is perfect for adding additional optics or components creating a full optics solution in one system.