I picked a few of these Yellow AC power blocks up on sale for $8 each. They have a 15 amp breaker and ground fault built in. The trailer wiring...lights, brakes are housed in the lower grey PVC box with the cable from the vehicle coming directly in via the bottom. The upper box has a 6 slot fuse block in it for all the 12 volt power points and lights. Battery is a sealed unit at this time but is subject to relocation soon.