Heating Oil Tank Lock for use on speedFiLL type adapters (FSS-750-QF) Suitable for use on below ground and above ground oil heating storage tanks. Also for use on refrigerated trailer (reefer) tanks. For use on all speedFiLL type adapters Tubular lock and key with over 50,000 combinations. Cap has a weather proof self closing latch covering the face of the lock to prevent dust,dirt,debris and moisture from entering the lock. Made from heavy duty corrosion resistant material for years of reliable use. * Locks can be key alike for multiple use convenience.