Has the lazy jacks built into the cover. I lower the sail as fast or as slow as I want and it always ends up where it's suppose to. During sailing it rolls up and lays against both sides of the boom with the lazy jacks pulled forward to the mast. After you drop the sail you zip it up and your done. It has two fiberglass rods that run along the top of the cover where the lazy jacks attach that holds everything in place and facilitates rolling up the cover. It works great and I would never go back to just lazy jacks again. Google Lazy Cradle, UK sails.