The Unifiber 9 mm barrel insert is a threaded insert fitted into the head of a windsurfing fin. It works with an M6 screw, allowing the fin to be secured to the board. It is designed for Powerbox, Tuttlebox and Deep Tuttlebox fins with an opening matching this insert diameter.

It is suitable as a replacement part if the original insert is lost or its thread becomes damaged. It is also a useful spare to keep in your repair kit when travelling.

Choosing the correct size

Before purchasing, measure the diameter of the existing barrel insert or the opening in the fin head. Also check the length of the insert and make sure the thread matches the screw. The fin box type alone is not sufficient to determine the correct insert size.