The Defender-ST Micro Red Dot Sight was built from the ground up as an ideal optic for everyday and concealed carry applications, and offers the performance and quality that all Vortex optics are known for. The massive aspherical window size is one of the largest in its class, ensuring a clean sight picture free of distortion. In terms of durability, the Defender-ST is outfitted with the exclusive ShockShield polymer insert which allows the optic to easily withstand everyday shocks, impacts, vibrations, and repeated recoil. The Defender-ST’s outstanding durability also extends to the innovative FastRack feature – this utilizes a knurled texture machined directly into the face of the optic, and allows the Defender-ST to be pressed against any surface to rack the slide of the host pistol. In addition, the Defender-ST utilizes a motion activation so its always at the ready, and an automatic shut off helps preserve battery life.