Cole Hersee - Heavy-Duty Battery Switch 500-Amp, Off–1–2–All Aqua Signal All are 12-Volt Size: 1-11/16"L

All are 12-Volt Size: 1-11/16"L x 5/8"Wx x 3/8"H

Boat Length 5-9 M

Vetus - Gender changer for joining CAN-bus extension cables - BPCABCGC

They all have heavy-gauge copper contacts

however some alternators now come standard with very high output voltages

Cole Hersee - Heavy-Duty Battery Switch 500-Amp, Off–1–2–All Aqua Signal All are 12-Volt Size: 1-11/16"LFour positions: OFFONBattery No. 1ON Battery No. 2 and ON Both Batteries. Can be operated through ON positions with engines running (shut down engines before moving to OFF position). Three 3 8" diameter heavy copper stud terminals with brass hex nuts, fracture resistant, high temperature plastic case, knob and insulator. Vapor water dust proof and corrosion resistant. Surface mount or install through a panel with a 3 5 16" diameter clearance hole.