NO TOOL REQUIRED: Hand Tighten Against Rubber O-Ring Means No Tools Ever Needed UNIVERSAL FIT: Fits All Standard FCS Compatible and Futures Compatible Surfboard Fin Boxes For Longboard SUP Inflatable SUP Single Fin SUPER VALUE: Packs Mean You'll Have An Excuse To Buy More Boards RUST PROOF: 316 Stainless Steel Will Not Rust In Fresh or Salt water. CHARITY: Every month we send 1% of our sales to a charity. This month it is El Camino which is improving the health eternal well being and self-reliance of people living in isolated regions.