Part name/wiring questions

[Patriot]

I need help identifying a part and understanding the mess of wiring the previous owner made. The first picture shows the part in front of the batteries. It says caution hot, max watt 120 max amp 28. It is approximately 4”h x8”L x 1”wide. It has two connections to it. The other pictures show the connections. One connection goes to the second in series battery negative. The other connection splits to the tangle of lwires, some I know for sure are tail lights, in the bottom left hand corner of the third photo. The forth photo shows a red wire connection to the fist in series battery positive that splits to more wires.

All the lights work but from what I gather in trying to analyze the wiring is that the previous owner wired the lights directly to the battery without a step down reducer. I have led strip lights I was going to install assuming he had a 48v to 12v reducer for the lights. I ordered the voltage reducer and wanted to put the headlights/brake lights onto the reducer so not to unevenly draw from the batteries. The part I am trying to identify doesn’t look like any reducer on amazon. I am now unsure where to disconnect the lights from as I can’t find any information on that part or what still needs to be attached to it.

All help and suggestions appreciated. Thank you.

Yamaha G19e 1998