If you buy with the swivel, does the swivel come with universal inserts also?

The swivel option does not come with universal inserts. Only the size chosen will be included. When ordering a rack and adding the option to allow the rack to swivel with the addition of the swivel adapter we must know the tubing size of your tower. When you order the swivel adapter to add to an existing rack or any rack with a swivel adapter, we send a metal shim that is required due to the motion of the swivel. Therefore we will need to know the size tubing of your tower to determine which size shim is needed. All Monster Towers currently being produced use 2.5" tubing. We do not know the specification of any other wakeboard towers in the industry and recommend measuring your current tower if it is not a Monster Tower.