Features Precision CNC machined aluminum construction Double O-rings for vastly improved airseal Exact length laser engraved onto nozzle for easy visual identification while tuning Improved durability over plastic nozzles Standard label for nozzles are by gun and version, MaxxModel measures by millimeter so technicians can tune the depth the nozzle travels, essential for BB groupings, rate of fire, and speed; depth of the nozzle travel is between .1mm to .5mm or more depending on the brand.General Nozzle Lengths:19.63mm - AK Series20.40mm - MP5-A4 / A5 / SD5 / SD6 Series20.73mm - P90 Series20.77mm - M16A1 VN / XM177E2 / CAR-15 Series21.03mm - MP5-K / PDW Series21.20mm - G3-A3 / A4 / SG-1 / MC51 Series21.22mm - M4 / M16 Series22.26mm - SIG 550 / 551 / 552 Series24.27mm - G36 Series24.60mm - AUG SeriesMaterial: CNC Machined AluminumCompatibility: For TM Compatible Airsoft AEGsManufacturer: Maxx Model