M2 red dot sight diameter 30 mm from Strike. In combination with the delivered ring shaped "L" can be attached quickly and easily to all weapons with conventional RIS rail (20-22 mm). Both lenses are protected from dirt by flip up lens covers. The red dot is fully adjustable and it is possible to use several illumination intensities of red/green target point (dot). Full metal red dot made in the style of red dot CompM2 from Aimpoint, which is used by many armies and special forces around the world. For proper function requires two button batteries 1,5V AG13/LR44, which isn't included.