The B-2 hop-up cylinder fits multiple KWA pistols and SMGs, and appears on respective diagrams as M1911DS part 123, M9 PTP part 9, M93R II part 34, M11A1 part 32, M226 part 9, M1911 MK Series part 10, M1911A1 NS2 part 10, kz.75 part 9, KMP9 part 91, and TT-33 part 7.