Heating Oil Tank Lock Standard Thread (FSS-750) Suitable for use on below ground and above ground oil heating storage tanks. Also for use on refrigerated trailer (reefer) tanks. Made from heavy duty corrosion resistant material for years of reliable use. Tubular lock and key with over 50,000 combinations. Locks can be key alike for multiple use convenience. 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. ** Fits all 2" standard male threads or can be used with a 750-200 adapter (included) to convert to a 2" standard female thread. Quick Fill and BSP threads also available.