Sight Level Gauge 15. Made of Aisi 304 St. Measuring tube made of borosilicate glass. Tube made of plexiglass. Combined sealing is used here EPDM+PTFE. The mounting hole in the tank should be 1/4 BSP. Working temperature is less 100. Working pressure is less 10 bar (145 psi). To order, we can produce a sight level gauge with an intercenter distance of up to 50.