The switch I bought is a momentary switch. Step on it, the polishing motor spins. Remove my foot and the motor looses power and spins down, it does not immediately stop. There is no way for the switch alone to instantaneously stop the motor from spinning, some kind of brake needs to be employed. I am just happy to know that, should I have a problem, I don’t need to flick a switch with the hand that might be part of the problem to stop the motor. It also kind of forces me to stop the motor if I drop something and bend over towards the motor to pick up what I have dropped. I have to move my foot to bend over. I also drop a lot of things these days. I hope that this answers the question asked about the switch being an on/off switch or a momentary switch. Again, there appears to be many options out there, just read the description first before you buy it to make sure that it is what you want and can handle the current required by your motor…Rob