GBRS GROUP LERNA MOUNT KIT. Aimpoint Mounting Pattern. BLACK.GBRS Group Lerna Mount Kit Lerna is the first stand alone optic mount designed for end users that offers a 2. 91 Optic Centerline for faster target ID, regardless of gear equipment obstructions, ie. EarPro Comms headsets, Gas masks CBRN, and Night vision use. A higher Optic allows for a more athletic posture and Heads up attitude that enables the end users to maintain a vertical spine which translates to body armor or presenting plates to the threat.