Locking nut now has embedded rubber O-ring to help prevent loosening. Can use end cap A8CAP, rubber end plug BP16, or fighting butts F2M, F2 and F5. Unassembled. Threaded Barrel O.D. - 0.750" Fixed Hood O.D. - 0.985" Length - 90mm (3.544") I.D. - 14.1mm (0.555")