OOps! Did you drop yours in the sand?  Replacement Fin Screw (2 Pack)NO TOOLS ARE REQUIRED: Hand Tighten Against Rubber O-Ring Means No Tools Ever NeededUNIVERSAL FIT: Fits All Standard US Fin boxes, SUP, Inflatable SUP, Single FinRUST PROOF: 316 Stainless Steel Will Not Rust In Fresh or Salt water.