The J1772 plug. It can't be plugged in any way other than the right way. Power is turned off unless it's plugged in and the car turns on charging (or is running the climate control). The "EVSE" indicates to the car the maximum current that can be drawn, which in this case is 12 amps, as 80% of the circuit breaker rating is allowed for continuous draw. Household 110V circuits are generally either 15 amps or 20 amps.