The HI98121 is a waterproof pH, ORP and temperature meter. The housing of this tester has been completely sealed against humidity and is designed to float. Electrode replacement with the stainless steel round connector means there are no pins to bend or break during replacement. When the cloth junction becomes clogged and response time is sluggish, simply pull out 3 mm (1/8”) to clear the clogging which will improve response time and stability. The exposed stainless steel temperature sensor on these models facilitates faster and more accurate temperature measurement.