The TacStar Shotgun Rail Mount is designed to fit standard 1 diameter magazine extensions and allows for easy mounting of tactical lights and/or lasers. The mount has three standard Picatinny rails positioned 90 degrees apart which allows for plenty of options when mounting accessories to the shotgun. The mount uses an easy to install clamping system which will not mar extensions, yet is strong and secure. Picatinny rails will accept most scope/light/laser mounting rings. The shotgun rail mount is available in two lengths. Choose the length that best fits your extension length and accessories. Keep in mind space for a barrel/magazine clamp if used. The short mount is approximately 1.8 and the long mount is 4.1.