The ECHO Process Instrumentation Arrow Hunter Plus is a clamp-on transit-time flowmeter for all metal or plastic pipes with any liners from 3/8'-in. to 118-in. diameters on clean or dirty liquids. It uses Dual DSP technology and measures flow velocity from 0.03 to 82 ft/second. Accuracy is ±0.5% factory calibrated (process conditions can reduce accuracy).