Swingarm Kit - Extended 3" over stock. This kit includes a high quality lightweight aluminum swingarm that increases strength and improves handling. Unlike many other swing arms on the market - these use billlet aluminum sections and the pivots use bearings instead of the stock type rubber bushings. Recommended for use with 330mm long rear shocks. We have two types of 330mm rear shocks sets available in this section that work great with this swingarm. Important Note: The swingarm itself is a bolt on kit - however - a roller (not included) is recommend - there is a perfect spot on the Z50 frames to bolt or weld on a roller. If you want to see a picture of this kit mounted - please email us at firstname.lastname@example.org These are the swingarms we use on our Vegas winning vintage mini mx race bike Z50s and definitely are not the cheaper poor quality cast aluminum Chinese $75.99 ebay specials you see around - just compare the welds and aluminum if you can get them side by side.