FSS 720 Locking Filler Cap PREVENT UNAUTHORIZED USE: The Flow Security Systems locking filler cap is a quick and inexpensive way to safeguard costly fuel and oil from theft, tampering, siphoning and vandalism. The locking filler cap utilizes our patented design, perfect for all business owners who want to secure and protect their tanks contents. FREE SPINNING DESIGN: The FSS 720 is different from any other locking filler cap on the market today. It is designed with our patented "free-spinning" technology. When the cap is in the secure mode the cap will free spin making it virtually impossible to remove. BREATHABLE CAP: The FSS 720 cap is ideal for protecting fuels, chemicals, and any other valuables stored in your storage tanks. This filler cap was designed to secure storage tanks with a male or female 2 NTP. The Flow Security Systems tank locks can be used in many different industries - medical, military, chemical, pesticides, agricultural, port districts, compounds, pharmaceuticals, hazardous waste, homeland security, tank manufacturers, environmental services, oil and gas companies. STRONG & DURABLE: These locking filler caps are made from hardened steel. These caps are built to last a very long time thus making these locking caps an easy low cost solution for preventing theft, tampering, siphoning and vandalism. Locking filler caps provide security for home heating oil tanks, storage tanks, chemical tanks and fuel storage tanks. KEYED THE SAME OR DIFFERENT: The locking caps come with 2 keys that operate both looking caps. If you require multiple locking caps, your order can be keyed the same. Perfect for those who have multiple storage tanks and don't want carry different keys to access contents. But if you want different keys, that option is also available.