Osight SE [red]This red dot uses the Shield RMSc footprint standard. Key Features Enclosed Emitter Optic: Fully sealed design for superior protection and reliable performance in any environment. Aspherical Lens: Zero distortion and parallax free clarity through a large window for fast, precise target acquisition. Side Load Battery: Easy CR1620 battery replacement without removing the optic, preventing the need for re zeroing. RMSc Footprint: Directly fits optics