Super simple, easy to print without supports or anything, spool for your recovery float. Attach it to the float, coil some string/small line around the 3/16 wooden dowel axle (not provided ) and then attach the other end of the string to the hull. The wheels are designed to be a tight fit onto the 3/16 dowel to lock it in place on the spool. Don't press them tight to the spool body, or it wont spin freely.