Lancer Systems Shotgun Extension Tube 9 Round LSX-9X-B. Designed to install in place of the factory magazine tube cap these smooth-feeding extension tubes provide increased capacity for most popular shotgun models while adding considerably less swing weight than traditional aluminum extension tubes. Specifications for Lancer Systems Shotgun Extension Tube: Manufacturer: Lancer Systems Color: Black Fabric/Material: Carbon Fiber Package Contents: Lancer Systems Shotgun Extension Tube Lancer Systems LSX-9X-B: Shotgun Extension Tube 9 Round