Flow Watch

ITEM # FW450

Flow Watch

The #FW450 is ideal for making precise field measurements of water or air speed (flow rate). It includes a telescoping aluminum rod for extending the probe deep into ventilation shafts, ducts and conduits or into a river or irrigation canal. The flow watch is a favorite of hydrologists and HVAC/R contractors/technicians.


Best For:



  • Displays instantaneous, maximum or average speed + instantaneous, maximum, minimum or Wind Chill temperature
  • Includes a 1.2m long telescoping aluminum rod, and a 10mm long aluminum rod that turns the unit into a compact anemometer
  • The 12mm diameter #FW450-12 Windspeed Impeller and the 15m long #FW450-50 Sounding Cable with Water Speed Impeller are available as optional accessories
  • Six speed unit options: cm/sec (default), m/sec, ft./sec (fps), mph, kmph, knots
  • Backlit 4-line LCD with 0.4 in. (10mm) high digits
  • Lap time (chronometer) function
  • °F/°C switch
  • Completely waterproof and weatherproof
  • Tripod mount
  • Specifications


    • Air/water speed measurement ranges: 3 to 150 km/hr (2 to 93 mph); 0 to 999 cm/sec in cm/sec mode
    • Speed measurement accuracy: ±2%
    • Speed measurement resolution: 0.1 for all speed units except cm/sec (3 cm/sec)
    • Temperature measurement range/accuracy/resolution: -4° to 158°F (-20° to 70°C)/±0.4°F (±0.2°C)/0.1°
    • Operating temperature: -58° to 212°F (-50° to 100°C)
    • Dimensions of display unit: 6.1 x 2.6 in. (155 x 65mm)
    • Dimensions of telescoping aluminum rod: 3.9 ft. (1.2m) long x 3.9 in. (100mm) diameter
    • Length of telescoping rod's cable: 6.6 ft. (2m)
    • Length of fixed aluminum rod: 3.9 in. (100mm)
    • Diameter of included air impeller: 0.79 in. (20mm)
    • Diameter of included water impeller: 2.36 in. (60mm)
    • Weight of display unit: 7.4 oz. (210g)
    • Power source: Two "AA" batteries (included)


    • Display unit
    • 1.2m long telescoping aluminum rod with cable
    • 10mm long aluminum rod
    • 20mm diameter air impeller
    • 60mm diameter water impeller
    • Custom padded aluminum carrying case
    • Batteries
    • 1-year limited warranty