Crown 58HP12 5/8" OD X 12" Long High Pressure Boiler Gauge Glass (Boiler Level Sight Glass) Does Not Include Gaskets Or Friction Rings. For Gaskets See GGW#3 And Friction Rings See 58BW Made From Schott’s Heat Resistant Borosilicate Brand Tubing. This Glass Is Widely Used In High Pressure Steam Boiler Applications. Easily Cut To Size Using A Gauge Glass Cutter (Sold Separate). Specifications: 5/8" O.D. 12" Length Maximum Recommended Working Pressure (PSI) At Temperatures Up To 150°F 410psi Steam Boiler Up To 425°F 305psi Replaces Westwood H3-12