Steel Liquid Level Gages with Shut-Offs can be used to view liquid levels in hydraulic reservoirs, gearboxes, bearing housings, crankcases, transformers and machinery oil reservoirs. Their use can be extended to any industrial liquid level viewing application. The shut-off function allows the gage to be removed without emptying the reservoir.This sturdy gage is made of plated steel. The glass sight is protected by steel on three sides. A red line on a white background enhances liquid level visibility. Leak-proof construction is achieved with Viton seals. The unit tolerates up to 125 PSI and 300° F. Fluid enters through the cross hole in the hollow lower bolt. The gage is vented into the tank through the cross hole in the top bolt. The length between the center of the two bolts is referred to as the center line. The distance between the center of the tank holes must be within 1\/32 of the center line measurement. This gage is mounted to the tank with (2) 1\/2-20 plated steel bolts. The back mount design requires that the inside of the tank be accessible in order to secure the bolts with plated steel hex nuts. Torque to 90 in-lbs.The brass stems can be adjusted to stop fluid flow into the gage. This can be used as a precautionary measure if breakage is a concern. Should the gage need to be replaced, the plated steel hex nuts unscrew from the front and the gage can be removed without draining the tank. Once a gage has been placed back onto the bolts and secured with hex nuts, the shut off valves can be opened and the gage will resume normal function.For fractional inch centerline distances, level markings or other seal options, please consult factory.