Lockjaw Longboard Fin Lock. Lockjaw board locks are probably the best on the market in terms of cost, flexibility and quality of construction. It provides security and more importantly peace of mind for longboarders and works with all boards fitted with standard fin boxes. The fin box lock construction is zinc alloy, supplied with a PVC plastic coated 6mm width, 2m length, galvanised steel marine cable lanyard, so it isn't going to rust. The steel marine cable is used in shipping and has a massive breaking strain, so it's going to hold your board! A determined thief can and will steal almost anything, but this product is a major deterrent and will stop the opportunist from making off with your prized possession.