With Taco AccuFlo Balancing Valves, you will experience greater balancing accuracy than ever before. Most conventional balancing valves use a variable orifice that delivers poor balancing accuracy, high pressure drops, low regains, and an inability to read low flows. The Taco Accu-Flo uses a modified venturi design, instead, to deliver four to five times greater accuracy. Flow Measurement is independent of stem and ball position, and the tamper-resistant memory stop provides accurate resetting. With calibrated nameplate for presetting, all-brass interior parts, precision machining and 100% factory testing, these valves are the highest quality fixed-port venturi balancing valve on the market today.