Timing pulleys (XL,L,H,XH,XXH) HTD Timing pulleys(3M,5M,8M,14M,20M), ... ,AT5,AT10),etc. timing pulley HTD ,Timing pulleys (XL,L,H,XH,XXH) HTD Timing pulleys(3M,5M,8M,14M,20M ... .5,T5,T10,T20,AT5,AT10),BTL Timing pulleys(L,H,XH)The surface treatment of timing belt pulleys is black ... oxide,phosphate,anodize and zinc plating. Timing pulleys (XL,L,H,XH,XXH)