Fitment: 73995 Pressure Switch Fit for 2006-current Caldera Vacanza, for Hot Spring 2006-current HotSpot and Solana, except Sprint & Dash models. Improve users' experience in hot tub and spa systems Features: 1) The switch monitors the heater to turn on and off automatically based on water level. If in low flow condition (due to low water levels, blockage, or other issues), the switch will deactivate the heater .