The S-shaped frame stacks 6 open compartments in an alternating zig-zag, so a 31.5-in wide footprint reaches 75-in of height and holds far more than a straight shelf of the same width. Each compartment stands 12-in tall and carries 44 lb, enough for hardbacks, box files, or a row of plants. The surface is waterproof and scratch resistant, so spilled water wipes away without leaving a mark in the board. An anti-tilting device fixes the 52.5-lb unit to the wall before anything goes on the shelves.