15-17mm Diameter Car Battery Disconnect Switch - Universal Top Mount Cut-off Master Kill for Ford BMW VW GMC Buick Volvo etc. Please measure your car battery pile head first, then decide to buy the right size car battery disconnect switch! We have 11-13mm and 15-17mm diameter for 2 sizes. Universal Car Truck Boat Battery Terminal Master Disconnect With Green Knob Save your car power, protect the whole system from draining out. Save the troubles for finding help from technician or others and much money and time cost on them. Especially for some old car, the battery system is very fragile and won't start if you park the car for a long time. Here is the cure! For 6V, 12V and 24V battery systems, 500 ampere surge rating and 125 ampere continous rating. Universal for cars, boats, trucks, RVs and more.