Reproduction ARMS SIR Collar

Reproduction barrel nut collar for A.R.M.S. S.I.R. handguards. 4041 Steel, parkerized. Modeled after a #58m collar, pictured on #45c, these should be compatible with any S.I.R. handguard that utilizes cross bolts at 3/9 o'clock, not those with bolts coming down from 12 o'clock.