The 4 mm trimming line is a basic component of any windsurfing setup. It is used to adjust sail tension in mast extensions and boom trimming systems.

With a 4 mm diameter, it combines durability with smooth, jam-free operation through pulleys and rollers. This makes accurate sail tensioning easier, both during rigging and while sailing.

The 10 m length provides maximum flexibility – ideal if you want to cut the line to your preferred length or use it across different setups instead of carrying multiple shorter lines.