My truck has a fuse box under the hood with 80 spaces in it. Even though the cover is numbered, you would have to dig thru a 400 page owners manual to find what is what. So I made a little cheat sheet coated with plastic for under the cover. I also made sure I had a couple of spare fuses ..... just in case. This would make it a lot easier for me on the road if needed. I also have one under the cover of the campers convertor ....this would make it better to fine a problem in the dark on the floor.