I have had 3 maybe 4 races and a few rides with this on my yz250f, thought it would be a good upgrade from stock but was mistaken. It wore down so quickly. I race GNCC and Harescrambles and have got a whole season in out of a stock chain guide. T.M. Designs will replace it as you see the warranty listed in the description, but this is a PRORATED warranty which means you will have to pay a certain amount, depending on the amount of wear on it. Not too happy with the attitude of the customer support. But great service from Motosport!