As others have mentioned the rail is 48" long, but the hole to hole (1st to last) dimension is 47.5". Now how are you supposed to hit the CENTER of four (16" on center) studs per the hardware kit instructions? The simple math doesn't work. Put another way, if your wall has more than 1/4" error over 4ft in stud spacing, you'll miss the last stud. All you need to do is add 1" to the rail, Rubbermaid, and hire an new product designer.

Anyway, once up (slightly angled screws on first and last stud) the rail system works well. I like the product alot even though the design has an obvious flaw.