The ATWB1, K-type wet bulb thermocouple can clip to HVAC/R equipment for convenient placement and hands free testing. Wet the durable sock and clip to evaporator filters for indoor wet bulb- great for finding target evaporator exit temperature. Clip to return vents for indoor wet bulb temperature- great for target superheat calculations. The ATWB1 can be used with any of our meters that measure temperature and any thermometer accepting a K-type thermocouple. HVAC/R technicians find the ATWB1 extremely helpful when data logging or anytime an extra hand is needed.