An overview of the First Factory SIG Air MPX AEG Outer Barrel Base & Battery Spacer from Laylax.... "The SIG SAUER ProForce MPX Outer barrel base that can be attached to electric guns. Our 'Outer barrel piece for Tokyo Marui M4' (sold separately) can be connected to the outer barrel base, and the barrel length can be changed to the desired length. In addition, a battery spacer corresponding to the outer barrel piece is attached, so you can prevent the battery from popping out.

• Can be installed without processing
• Prevents the battery from popping out
• You can change the barrel length to your liking using our M4 outer barrel piece"