275-3124-00
Spa Parts 275-3124-00 1/2" Thermostat Plastic Spa Heater Control
I chose this AAIWA product because it requires little training.
Invensys Appliance Controls 275-3124-00 Thermostat, , 14, 36, SPST, 25A
You will find that the HBN 0.5microns unit does not clog up as quickly as others.