Can someone explain to me exactly how the switch works. How do you determine the right chip to use.

 

copied from the nitrous accessory basics "sticky"

7. Window Safety Switch: The window safety switch is designed to keep you from spraying under to low of a rpm or over revving your engine. The window switch gives you two settings, an activation rpm and a deactivation rpm. You will set the activation point to at least 3000 RPM. When the system is activated, the TPS or wide-open throttle switch sees wide-open throttle it will complete the positive circuit to the systems relay. The window switch will read the engine RPM. When it rises to the set RPM on the window switch, the switch will supply ground to the systems relay, completing the circuit and firing the solenoids. In the incident the driver misses a gear, transmission slips, rear end or driveshaft breaks causing the engine to over rev the window switch will take away the ground to the solenoids at the set RPM on the switch shutting off the nitrous system. We suggest setting the deactivation RPM for the window switch at the shift point or 200 to 300 RPM before rev limiter