The 17000 Gauge functions as a level indicator and also serves as a pump setting gauge. The rate scale can be calibrated in a variety of options, such as GPM, GPH, GPD, LPM, LPH, or LPD. The maximum pump rate for a 12″ gauge section is 25 GPD. The sight tube in the 17000 is 1″ O.D. glass, which makes it ideal for viscous fluids. The top and bottom connection for this gauge is 1″ MNPT.