Definition: Shoe spacers are thin sheets of plastazote or other light material that are included in extra depth, double and triple depth shoes to fill space. Most range from 1/8 inch to 3/8 inch. Likewise, a spacer can be removed to make more room in a shoe. Depth shoes are made to be filled with arch supports, braces or other devices so sometimes one shoe or the other must be have more or less space filled because of the device being inserted.
In regular depth shoes that are too large, a spacer will sometimes fill enough space so the shoe will fit better. Narrow shoes are hard to find and spacers can help those with narrow feet fit in medium widths better.
Benefits: Not all feet are the same size, whether from natural causes, injury or medical condition. Minor differences between feet size usually does not affect shoe size. Where it does, spacers can fill space in the shoe with the smaller foot and make that shoe fit better. Where there are arch supports or braces, spacers can be inserted or taken out to make both shoes fit better.