Joe Brancato sells something very similar: Wrench Tight DIN300 SCUBA Fitting to STAINLESS STEEL Male Paintball (Foster brand). For filling DIN300 Carbon Fiber tanks or DIN300 SCUBA tanks at places that fill paintball tanks. Notice no adapters are used, waste less air $53. It's on his site (airtansforsale.com) about two thirds of the way down. Had one for years - wouldn't be without it