Well I'll show my lack of electrical knowledge here. I'm an electrical swapper not an understander meaning I can swap out like for like but unless its a battery or alternator I'm generally don't know what it is. So that for lack of a better term is a "switch". There is a piece of label tape on the hood with an arrow that says battery on is how I figured it out. So that hex key turns that switch 90 degrees and it cuts the battery on and off. Obviously the battery wires are wired to it. Not sure if the previous person did that to store it in the winter to keep stuff from being a drain on the battery or what but that's what it is. The rubber hoses are just covering up 4 other potential contacts. Now someone else can probably translate into what it really hopefully with my uneducated description.