air7 Stainless Steel 316 fin screw 14x14 [ 3 pack] for Longboard Surfboard, Stand Up Paddle (SUP) and airSUP - most US box fin boxes AiR7 STAINLESS STEEL 316 fin screws for most SUP including inflatable airSUP and many other paddle board - if not sure contact us. VERY resilient against rust due to saltwater! STAINLESS STEEL BOLT : 3.5mm Diameter x 18mm Length (about 1mm rubber o-ring washer) STAINLESS STEEL NUT : 14.1mm Wide x 14.1mm Length x 4mm Height EASILY TIGHTEN with your hand, no tools required - tool less. Note: three in the pack fits most US box style fin boxes (longboard / SUP and airSUP and other paddleboard)