Production Model : AIP013-51-07G - Large Magwell can speed up your reloading time - We recommend this magwell to all skirmish players and competitive (IPSC) shooter - Suitable AA IPSC Standard Rule - Suitable for Tokyo Marui Hi-Capa 4.3/5.1 Series Airsoft Gas blow Back GBB Pistol - As always, upgrading GBB require necessary skill & technique, consult expertise if needed