The Model ZS002 Electric Thermostat Test Tool is a handheld thermostat substitution tool and an air conditioning system testing tool for up to two stages of heating and cooling in conventional or heat pump systems. The Model JC-5309 Allen Head Flex Screwdrivers allow removal of sensor and thermostat covers for service. The Model ES1051 Freeze Spray is for testing sensors and thermostats. The spray cools down the elements for testing thermostat operation or point-to-point wiring verification. This non-corrosive and contaminant-free aerosol has no CFCs and saves checkout time. The Model 680243-6 Changeover Switch has a snap-acting SPDT and is made to strap on to water pipes. It is used for heating/cooling changeover inputs to room thermostats. It has a fixed set point of 85℉ and a 20℉ lowside differential (off at 65℉). The maximum fluid temperature is 220℉ and maximum ambient is 125℉.