Adapter for bikejoring and kickbiking with dogs. Keeps the leash out of the wheels and lets you to keep your both hands free for steering. The spring smoothes all sudden movements too. In this adapter, the spring can be easily turned sideways when you want to run the dog beside the bike. includes two different U-bolt attachments (38mm and 54mm diameter) spring can be easily removed when adapter is not needed weight 540g, length 52cm Note. Additional Kainpo Nylon Attachment Ring is sold separately.