This is a 3 piece adapter set that allows you to bolt a "carb" model YFZ450 rear shock and linkage into an aluminum YZ Frame, 4 and 2 stroke model compatible. (note: does not work with EFI YFZ450R shock, carb non R only.) This set has a top sleeve that replaces your shock top sleeve and changes it to a 10mm hole to match the YZ frame, The lower 2 spacers are shouldered and take up the space difference for the YFZ linkage and neck the mounting holes down from 14mm to 12mm. You can find the proper size and length bolt at you local hardware store, take your old 14mm diameter bolt with you, the new bolt head will lock into the frame like the stock one, use one Nyloc nut to secure the other side and have space for the chain roller. If you need to order individual spacers send us an email and we will get you invoiced as soon as possible. This set will give you 1 top and 2 bottom spacers.