The 2" 975XLHBM Hydrant Backflow Meter Assembly is used to measure the potable water from a fire hydrant or other non-permanent temporary installations when water flow is one direction only. It is utilized in high health hazard applications for protection from both backsiphonage and backpressure of contaminated water into the potable water supply. Assembled with an approved backflow preventer and water meter, the 975XLHBM features NH (NST) adaptors for connection to a 2-1/2" fire hydrant inlet and 2-1/2" fire hose outlet. It gathers accurate measurements of up to 250 GPM, with a maximum rated flow rate of 160 GPM. Materials include a corrosion-resistant cast bronze body, and 300 series stainless steel fasteners and springs.