Made with high quality borosilicate glass Tubes are located at each end of Steam trap Cylindrical steam glass trap with tubes on each end. Made from high quality borosilicate glass. The unit is 7.5" in total length with a 1" diameter at the center of the body and .5" inner diameter at the opening of each of the 1.25" stems Eisco Labs Borosilicate glass has the following heat tolerances: Strain Point -515°C | Annealing Point 565°C | Softening Point 820°C.