553-25 553 Hammer
553-27 553 Bolt Lock Set
553-23 553 Magazine Catch
553-09 553 Bolt Cover
553-11 553 HOP-UP Bucking & Nub
553-12-1 553 Chamber
553-12-2 553 HOP-UP Set
553-13 553 Buffer Base
553-16 553 Charging Handle
553-17-1 553 Bolt Catch Stopper
553-21 553 Automatic Firing Lock
553-26 553 Release Bar
