Ultrasonic speed and temperature sensor provides maintenance-free reliability all season long. AIRMAR, the company who invented the Smart™ Sensor, has raised the bar with a new ultrasonic speed and temperature sensor. The UST800/850 calculates speed ultrasonically up to 22 times every second, automatically adapting update rates based on vessel speed. Because it’s ultrasonic, there is no paddlewheel, meaning trouble-free operation and no maintenance. With fast-response water temperature accuracy, the UST800/UST850 makes finding optimum swimming and fishing temperatures easy. This translates into the most reliable and precise ultrasonic speed/temp sensor on the market—at a very competitive price.