Mikasa Opening Shelves (18-Inch/24-Inch, Topaz, Set of 2) This Mikasa shelf set includes one 18- and one 24-inch shelf. Each shelf is 3 inches high and 3-3/4 inches deep. Each wood shelf has a thick line detailed edging with a cut out in the middle for an eye-catching look. Detailed line edging cut out of the middle of each shelf adds a distinctive look. Shelves are made of medium density fiberboard (MDF).