This stainless steel washer (35 mm diameter, 2 mm thick) is typically used in JP-Australia windsurf boards but also fits many other models. It's intended to sit under the head of the fin bolt, especially in boards where the fin box area is recessed into the deck.

By increasing the contact surface, it helps distribute pressure evenly and protects the deck from damage during bolt tightening. Compatible with most standard fin bolt systems including Powerbox, Tuttle and Deep Tuttle. A small yet effective accessory that contributes to safer and more durable fin installation.