This range of RH sensors are not suitable for use in swimming pools and spa applications. Relative Humidity/Temperature Transmitters. High specification, relative humidity and temperature transmitters for use with building management systems. User configurable for 4-20mA or 0-10V outputs Microcontroller reduces measurement errors Two part terminals for ease of connection Polycarbonate housings Measurement range 10 to 90% RH. IP Rating. ; 312-2939 312-2939 - IP30 ; 312-2945 312-2945 - IP65 ; 312-2951 312-2951 - IP67