Spinsecure FSS-750 NPT is a high-security locking cap designed to protect your fuel from theft. The cap is made from non-corrosive material for years of use and can be keyed alike for multiple use convenience. It is weatherproof and self-closing, covering the face of the lock for added security. The unique patented "spinsecure" technology secures the cap to the filler neck, making it virtually impossible to remove when in secure mode. The cap will freespin, deterring theft. The Spinsecure FSS-750 NPT is easy to install and use, providing peace of mind that your fuel is safe from theft.