Our USA Lab Sight Glasses are made of 304 Stainless Steel with Borosilicate glass. The Tri Clamp Sight Glass allows for viewing of the material in a system without adding bulk to the unit. It also has metal around the glass to hold in and better support pressure. Tri-Clamp Short Sight Glass Specifications Model Material Pressure Rating Glass Height Temperature Rating Outer Dimensions WxH 15SSG 304 Stainless Steel 110-120 PSI 1" -70°F to 240°F ~3.5"W x ~4"H 2SSG 304 Stainless Steel 110-120 PSI 1" -70°F to 240°F ~4"W x ~4"H 3SSG 304 Stainless Steel 110-120 PSI 1" -70°F to 240°F ~5"W x ~5"H 6SSG 304 Stainless Steel 80-85 PSI 1.5" -70°F to 240°F ~9"W x ~5.5"H 12SSG 304 Stainless Steel 60-70 PSI 3" -70°F to 240°F ~14.5"W x ~4"H For Technical Support, Questions, or Other Issues Please Email or Call Us!