Trijicon / PVS14/ N-Vision Enhanced Eyeguard Retention RingThe JL MetalWorx Enhanced Eyeguard Retention Ring replaces the standard eyepiece retention ring found on the back of pvs14 style eyepieces (ie Trijicon and N Vision Halo) and makes it much harder for the expensive shuttered eye guards commonly found on trijicon and n vision units to come off. This piece looks great and will pay for itself many times over.