Our electric fan relay kits come with a threaded thermostatic switch that screws into the engine block or intake manifold for a clean and professional look. These kits provide protection in the way of a 30 Amp circuit breaker for your electric fans and wiring harnesses. They supply constant voltage through a 30 Amp relay, protect against voltage and amperage spikes, and also prevent the fan from back-feeding voltage through your vehicle's wiring harnesses. Operating temperature is between 165F and 180F.