All three belts feature a high-strength 2 ply polyester carcass. The 2 Ply 220 Tan Bare X Bare is ideal for applications requiring a low coefficient of friction on both the top and bottom. 2 Ply 150 Black is an economical general purpose package handling belt. It is also used in agriculture. 2 Ply 160 Black is for heavier applications needing a tough cover with a low-friction bottom. Moderately oil resistant for processing wood chips, paper, and scrap.