The MEC R-Type piston head for Tokyo Marui / KWA pistol GBB is an improvement over the stock one that comes with the pistol.This particular revolver’s cylinder-front-view design brass piston head equipped with a 6-hole air intake in order to improvethe airtightness and air sealing with the included O-ring (including 3 size of O-ring: red, black and green).Features: Reinforced with brass. O ring for better air seal. Specification: Material: Brass, Rubber Weight: Marui-14 (1.8g) Marui-15 (2g) KWA-14 (2.5g) KWA-15 (3g) Manufacturing Process: Precision Machining Compatibility: KWA-14: KWA TT-33, M9, M93R, MP7 KWA-15: KWA HK45, MK23, MP9, Mark 4, VZ61 Marui-14: TM Hi-Capa, P226, G17 Gen.3, 1911 / KJ KP-17 / WE G17 Marui-15: TM PX4, FN 5-7, G17 Gen.4, G19  Disclaimer:    This product is for airsoft, training, and simulation purposes only. Utilizing Airsoft products improperly, including in real firearm applications, are potentially dangerous and may cause serious injury. PTS will not accept any responsibility or liability for misuse of this product.