The Solid State Thermostat is a dependable replacement for older mechanical or air-activated thermostats in spa and hot tub systems. Designed to provide more accurate and stable temperature control, this solid-state model eliminates the issues associated with traditional capillary-style thermostats. Its compact sensor and single-pole, single-throw (SPST) switch make it a versatile fit for many legacy spa packs, especially those using Tecmark control systems.