Bed Rail Bracket to Widen Beds are a great option for older beds needing a wider mattress. This style requires side rails to use a double hook fastener, does-not work with other types of rail fasteners. Brackets enable width of bed, to be widened up to 3" on each side. Sold as a set of 4 to widen one entire bed. If side rails are not long enough they will need to be replaced or lengthened (by a cabinetmaker).