This is a medium impeller 1/2 round key parts kit. Includes 1-1/2 round key, 1 retainer washer, 1-shim set (8shims), 1 impeller bushing and 1 shaft nut. These are a must have to keep around as a spare parts kit for any outboard jet boater! There are several different key types available so If you are unsure which key is correct for your application please email, call, text or send us a message thru social media and we'd be happy to confirm the correct part number for you! 573-529-3849