These over-the-road heavy duty adjusters are a fast and accurate means to align front or rear axles of most popular tandem trailers and trucks. You, the alignment technician, now have reliable means to complete total heavy duty truck alignments. #35020 Thickness: 1/32" Qty: 6, #35021 Thickness: 1/16" Qty: 6, #35022 Thickness: 1/8" Qty: 6. Note: Ordering one Part Number gives you six shims in a box.