Our fabricator of 89232 Orderpicker Platforms and 89233 Aluminum Picking Platform uses laminated wood blocks 1-7/8" by 11-3/4" and trimmed to a height that is custom to the specifics of the platform. If you have casters, you'll need a taller block for the order selector's clamp to grab, as an example. While you can use virtually any species of wood or rubber, laminate has proven over the years to give the longest life.