Lancer Carbon-Fiber Shotgun Extension Tubes (LSX) are designed to attach to existing shotgun magazine tubes to provide added capacity to the shotgun. Machined aluminum components combined with a lightweight carbon-fiber tube create a lightweight, durable extension to your shotgun. An extra-long spring is included that can be cut to optimize loading. Mfg: Lancer Systems SPECS: Carbon Fiber, Aluminum. Fits: Benelli M1/M2. 12ga.