SOPMOD buttstock has storage compartments on each side, installs on Colt dimensioned receiver extensions (buffer tube) only.

SOPMOD mounting parts sold separately.

Note: Will only fit on mil-spec (Stag/Colt/LMT/Vltor/Magpul) dimensioned buffer tubes!  They will not fit Bushmaster/Rock River Arms or most other makes.  Mil spec dimensioned buffer tubes are available if needed.