This compressed gas gauge features a bourdon tube with low copper content for pressure ranges 800 psi and below making it safe for use with acetylene. Lower mount connection. Wetted parts are made from a brass copper alloy. Polished brass case provides long-lasting durability. Removable twist-off polycarbonate window. White aluminum dial. Ambient operating temperature range is -40 to 140°f. Compatible with us gauge p-590k and p-600 and ashcroft 1495a. Cleaned to asme b40.100 level iv. Ul approved.