Ninja Paintball's HPA tanks are DOT approved tanks mounted with one of Ninja's supreme regulators. Every one of the regulators mounted is an ATSM compliant (Bonnet Thread/DOT Burst Disk/Restrictor, Bleed Hole, and Safety Groove) regulator made right here in the U.S.A that has an SRT piston (Sonic Recharge Technology), MFV (Mini Fill Valve) and a SPA (Shim Pressure Adjustment). These tanks are hand crafted, factory tested and have a super low response curve of 0-50psi from full to empty. Regulator Features: MADE IN THE USA!!!!, SRT piston – Sonic Recharge Technology piston – plated aluminum piston that produces an industry leading recharge rate and virtually eliminates reg shoot down, SPA – Shim Pressure Adjustment – change output pressure by adding or removing shims, not springs or pistons, MFV – Mini Fill Valve – Non wrist digging, low profile design fill valve, All black tactical look, Meets all DOT, CGA and ASTM specifications, Completely rebuildable by the end user, Every regulator is hand crafted and factory tested, Super low response curve 0-50 psi from full to empty. Safety: ASTM COMPLIANT bonnet thread, ASTM COMPLIANT DOT burst disc ASTM COMPLIANT Low pressure burst disk, ASTM COMPLIANT Restrictor, bleed hole and safety groove, Mini Fill Valve IS hardened, plated 5000 psi rated, Reg installed to ASTM specifications.