Product Description: Forespar Lightning Master™ (Static Dissipater) Lowers the exposure to a direct lightning strike by controlling the conditions which can trigger direct strikes, i.e. build-up of static ground charge and formation of ion streamers. Continually leaks off the ground potential in low amperages over a long period of time. The 21" long dissipater attaches with two machine screws to the masthead. For power or sailboats. From the same manufacturer which protects commercial broadcast and television towers.