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. #35040 Thickness: 1/32" Qty: 6, #35041 Thickness: 1/16" Qty: 6, #35042 Thickness: 1/8" Qty: 6. Note: Ordering one Part Number gives you six shims in a box.