The ACI Platinum Probe Only Series features a ¼” diameter stainless steel probe with two or three, 14 or 24 inch, 22 AWG Etched Teflon colored lead wires to differentiate the different sensor types. The three-wire “-3W” option should be ordered if using with a 3-Wire temperature transmitter or sensor configuration on your building management system or PLC (Programmable Logic Controller). The purpose of the 3rd wire is to compensate for any external lead wire resistance that will affect your sensor output. ACI recommends the use of an 18 AWG lead wires to reduce the external lead wire resistance when using a Platinum RTD sensor. The sensors in this series are manufactured using ACI’s proven double encapsulation process to eliminate the effects of moisture on the sensors and to increase the thermal response time using our high quality, thermally conductive epoxy. The probe is designed to be used in duct and immersion applications when used with the proper length thermowell. Optional lead length, cable types and NIST Certificates are available as referenced in the ordering grid on the Product Data Sheet. Applications: Roof Top Units, Air Handlers, Supply/Discharge Air/Return/Mixed/Exhaust Air Duct Temperature Sensing, Immersion Temperature Sensors, Replacement Temperature Sensors, Hydronic Water Systems