Build a shelving unit to the size you need or add on to single and double complete units with these ready made uprights and shelves. Solid wood uprights are unfinished hemlock with spacing of 5mm holes 1" on center for adjustable shelves. Available upright widths are 12", 15", 18" and 24". Upright heights are 4 foot, 5 foot and 6 foot. If you have questions regarding building a unit please call 1-800-426-5708.