Features: 14mm C.C.W. Extra light Fits best on Airsoft MP5 PDW and M4 series but is also compatible with all Airsoft guns using 14mm C.C.W. Story about the real BLACKSIDE: New for 2006, the Blackside replaces the SOS-45 suppressor in a shorter, lighter weight, more efficient package. Extensive testing has demonstrated that a recoil booster is not necessary for most weapons, including the difficult to cycle HK USP Tactical. Highest performance is achieved with only a minimal amount of artificial environment (such as light oil). Although not as efficient dry, it is acceptable when artificial environment media is unavailable. The mount features positive stop threading to reduce thread wear and provide proper alignment on 1911 and other pistols. Constructed of high tensile strength aluminum alloys heat treated to Gemtech specifications, this unit does not utilize any bore obstructing "wipes" or mesh. The advanced frequency shifting baffle design creates outstanding performance. With complete suppression of the muzzle flash signature, this device is an exceptionally effective tool for tactical users.