I purchased this because I needed to split my adapter so I could plug in a radar detector and a phone charger.  The product supports permanent installation and comes with bracket hardware and a velcro pad; either or both can be used.  The actual adapter fuses the hot lead directly to the center peg and the ground to the side posts.  The product supports a maximum capacity of 20 amps and the fuse is located on the back of the unit.  The unit also comes with basic instructions.