Genuine replacement rear sprocket made in the USA of T6 7075 aluminum and made to fit Honda CR125 and MR175 hubs with 10mm studs. This pattern is the OEM style lightening holes. Available from 43T to 54T. Larger sizes may add a few dollars to the cost.We stock the 48T, 49T and 50T and others will take about 10 days lead time. Uses a 10mm bolt hole.