Windsurfing Fins You paid $$$$ for your board and rigs so don't skimp on the fin quiver. A good set of fins will keep your board planing while others are in schlog mode. We have a nice selection of weed fins in Trimm box for the BIC Techno boards along with several power box fins for the Mistral Prodigy. See the fins section in our online catalog. Click on the images to see a large view of the fin. We also have a few used fins for sale. Please note that GSport Weed fins come in 3 degrees: Weed - 45 degree rake - best for heavy weed conditions Some Weed - less rake then Weed - a little better performance Sorta Weed - less rake then Some Weed - for light weed conditions - great performance .. we love this fin for Maumee Bay conditions! Need help with metric to inches? Then visit our metric convert page. Deep(DTT) and regular Tuttle(TT) Conversion GSport DTT and TT fins now come in DTT mode with easy conversion over to TT mode. Just lay a regular TT fin over it and mark a line, hack saw and move the barrel nuts to the lower position. Regular Tuttle fins require a bolt 20mm longer than Deep Tuttle fins.   6mm stainless metric fin bolts Now available in the online catalog under the fins section are 6mm stainless fin bolts and washers. These phillips pan head screws are made of A-2 stainless which is equivalent to 18-8 stainless. It is an alloy with high corrosion resistance and is the material of choice for most exterior and marine applications. Don't be screwed at the beach by a missing fin bolt - carry some spares!   mm inches 25 .98" 30 1.18" 35 1.37" 40 1.57" 45 1.77" 50 1.96" 55 2.16" 60 2.36" 65 2.55" 70 2.75" 80 3.14" 5mm is .1969" or approximately 3/16" of an inch