This Lancer Systems Barrel Clamp solidly connects a Lancer LSX magazine extension tube to the shotgun's barrel. The use of a barrel clamp is recommended when installing a magazine extension with a capacity of over 4 rounds in order to support the weight of the ammunition inside the tube and to help prevent the tube from being damaged if bumped or dropped. Constructed of lightweight aluminum that is anodized for corrosion resistance. For use with Lancer LSX tubes in 12 gauge only.