African air ordinance from south Africa for 4500 psi kits. Is the only way to make more power and that being said primarily on the super heavy end of the slug spectrum. You need a booster pump like that from alatros to make shooting at 4500 psi possible and reliable. That being said his valve are supposed to be good to 4800 psi and good with helium. So with helium and the upgrade 4500psi kit you could around 1000 fps with a 500 grain .457 slug. He is the only Texan upgrade no Chinese cheap stuff on the market yet.