48" Rail is 48". The widest holes are 47" so you won't easily hit 16" spaced cleats. RubberMaid should die Sell rail as 49" rail and you will have holes in the ends of the 48" rail. Alternatively you can drill holes between the end of the rail and the end holes and add a stud to each end plus two inner studs 16" apart Fasten ". Also note that the set of fasteners (screws, etc.) is of rather poor quality with small Philips heads. Better to use 3" stand-up screws and molybdenum bolts for cavity wall fastenings.
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