Home / Avionics / Instruments & Gauges / Probes / Sending Units / Leads / Probe, Water Temp, Micro Probe, Water Temp, Micro$23.25 Probe, Water Temp, Micro quantity Add to cart SKU: INWTP200 Category: Probes / Sending Units / Leads Description Description Single wire water temp probe / sending unit. Wire to the “S” on the gauge. The threads are the ground to the head. Threads are 1/8 male pipe. Do not use thread tape on this probe as the tape may insulate the threads to ground. A 1/4″ female spade terminal make the ideal connector.