The Holosun Solar Charging Sight (SCS-MOS) is a direct attachment optic for the GlockA(R) MOSA(R) systems offering Holosun's lowest profile pistol optic for use with standard-height iron sights. This unit fits on the pistol with no adapter plate needed. The SCS reimagines Holosun's Solar FailsafeTM system as a primary power source. The internal, rechargeable battery utilizes integrated solar cells and automatic brightness adjustment to make sure your battery will last as long as its shelf life. Given occasional bright light, the SCS will recharge itself. Additionally, our Multi-Reticle SystemTM (MRS) displays a 32MOA Circle or a 2MOA dot or both. Mfg: Holosun