I was surprised by the size of the automatic killer. It comes in at about 6x4x5 inches and is set up to be bolted to a flat piece of steel with four bolts. We went with the optional rubber terminal covers. You need to be very careful with the big terminals on this. If a piece of metal or a wrench or anything that conducts electricity falls across the terminals it could be bad. It probably wouldn’t be quite as bad as if you dropped a wrench across the terminals of the battery. But lets just say there are better ways to get your day jump started.