Easy fin attachment and removal! Quick Fin Lock Screw - No screwdriver needed (for surfboard and SUP center fins/box fins) By attaching this to the center fin of longboards, mid-length boards, SUPs, etc., you can adjust the position by inserting the plate into the fin box, freeing you from the hassle of tightening screws. It makes attaching and removing fins smooth before and after surfing. Please refer to the product image for installation instructions. (The spring may be stiff when starting to use it, so please be careful not to get injured during the work.) Features a stainless steel tab designed with water resistance in mind. Easy attachment and removal without tools. Rust-resistant stainless steel fin lock system for box fins. Insert the fin with the lock attached into the box, and the spring lock mechanism secures the fin inside the box. You can easily remove and adjust the position of the center fin underwater. Included: Pin, spring, base metal fitting, set screw, hex wrench Material: Corrosion-resistant stainless steel 316 Specifications: Pin length 36mm, pin diameter 4.2mm (Processing is required for fins with holes of 4.2mm or less.) No discounts are available. Due to the fact that regular mail delivery on Saturdays, Sundays, and holidays was discontinued in October 2021, shipments on Thursdays and Fridays will be delayed. Please note that returns and exchanges are not accepted. Surfing Surfboard Longboard Single fin Center fin FCS fin future FCS Screw Hex Driver Leash cord Deck pad Fin FCS2 Box fin Compatible Infill tab kit Fin plug