When the difference between a lights-out day on the water and a hike in the woods comes down to water temperature, the accuracy of your thermometer is crucial. Compact and easy to handle, the Fishpond Riverkeeper Thermometer is the only IPX7 submersible-rated digital thermometer designed by and for fly anglers for taking lake and river temperatures. With a rugged exterior, a large UV-filtered screen, a replaceable battery, and a durable aluminum probe, this lake water temperature guage is built to withstand years of rigorous use outdoors. The Riverkeeper is the perfect tool for taking precise temperature readings, helping you determine whether it's safe to fish and when your quarry might be most active. Size: 3.3 x 1.5 x 0.6 in (8.5 x 3.7 x 1.5 cm) Weight: 0.8oz (23g) To turn the thermometer on or off, hold down the button for 2 seconds. The thermometer will automatically turn off after 3 minutes of inactivity. To switch between °F and °C, quickly press the button three times Submerge thermometer in water and wait for temperature to stabilize If you see the error code "HHH," it means the temperature is above 130°F. If you see the error code "LLL," it means the temperature is below -30°F