Since I won't have access to the bolt heads once the tach is in, I mounted the supplied eye connectors before installing the tach. I installed three connectors, one for 12v switched power, one for ground and one for the Ignitor signal that drives the tach. Honda makes the power and ground easy by marking them right on the circuit board with a (+) for power and a (-) for ground. To figure out which terminal is for the Ignitor signal make sure to check the factory service manual for your vehicle like I did.