The original C31 OTT Current Meters set the standard for flow measurement in rivers, open canals, etc. and without them hydrometry is not imaginable.
OTT Current meters mean thousandfold proven quality, precision and reliability - worldwide for decades. The rotation rate of the precisely calibrated propeller is proportional to water velocity.
C31 Universal Current Meter is designed for flow metering in combination with hand-held wading rods or cable suspended from a bridge or boat. Different accessories like sounding weights (middle pieces), sounding reels (winches), cable ways etc. allow the setup of a complete flow monitoring station.