This  is a great item! Get your old bike riding like new again. This is a new in the package 7pc Clutch Friction Disc Set for the 1977 DT400( DT400D) and 1978 DT400 (DT400E). Please note these will not fit the earlier 1975 1976 DT400's as the used a different clutch friction disc. We do have the earlier DT400 clutch plate style listed on our website though..just use the search feature to search "1975 DT400"  Start enjoying your bike...get the back tire spinning..not your clutch! If your clutch feels jerky or slipping this is the fix. This is an easy swap for the home mechanic to do..or get your local shop to help you.  If you are riding, restoring or racing you and your bike will be happy with a new clutch! Your bike probably still has the old original clutch plates in it! The top-quality new clutch friction discs set is an important part of getting your engine power to your back wheel smoothly..and allow you to enjoy the trails, woods or track. Your clutch disc set will be mailed to you new in the package. Top quality aftermarket item.  Correct replacement for Yamaha part # 363-16321-00, 363-16321-09 . That's is it! We only sell the best. Thank you, and we look forward to doing business with you! We also have the helpful gasket set and perhaps other parts for these bikes in stock too..if you may need!