Post Mount Disc Brake Adapter Disc Brake Rotor Cycling Accessories for Most Bicycles

Standard 74mm long +20mm post mount adaptor for front or rear calipersDepending on your bikes setup this will make either a 160mm to a 180mm or a 140mm to a 160mmIn my case I have a 140mm rotor on the back which I used this to make it a 160mm, just so I can have the same disc size on front / back for ease of keeping parts spare.Came as a shimano branded adaptor, whether it's genuine I couldn't say, but it does ook exactly like the shimano part.Easy to fit, just remove you existing caliper, put this on your post mounts, and use the new bolts to attach your caliperIt does come with cone washers, which depending on your caliper may or may not be needed, I have Tektro M280 and the extra washers aren't needed because it's a post mount caliper and the lugs for the bolts are deeper and have adjustment built in as standard, if you have older style calipers you'll likely need the washers placed between the caliper and bolt head.