The JL3PC pipe temperature wireless clamps feature patent pending Rapid Rail™ Sensor Technology that uses electrically conductive pipe to complete the circuit so readings stabilize in 3 seconds and are not affected by ambient air. One beep with a slow green blinking light indicates a closed circuit. If the pipe is corroded the circuit will be open and will not read temperature. The clamp will indicate the open loop with a double beep and rapid blinking light. Simply clean the pipe to enable the circuit to be closed and allow fast readings with +/- 1° F accuracy.