{"product_id":"flow-security-systems-vented-locking-fuel-tank-cap-2-male-thread-hardened-steel-lock-built-in-vent","title":"Flow Security Systems vented locking fuel tank cap — 2\" male thread, hardened steel lock, built-in vent","description":"\u003cp\u003e\u003cstrong\u003eThe Flow Security Systems FSS-377 is a vented, locking 2\" fuel tank cap engineered to secure transfer and above-ground commercial tanks against theft, tampering, and vandalism while allowing controlled pressure equalization.\u003c\/strong\u003e\u003c\/p\u003e\n\n\u003cp\u003eBuilt for fleet managers, jobsite supervisors, and anyone who stores fuel in mobile transfer tanks or above-ground commercial tanks, the FSS-377 combines a hardened steel locking cap with a precision adapter and an internal vent valve. It provides a rugged, reusable solution that fits standard 2\" male threads and works with common 5\/16\" shackle padlocks (padlock not included). The design emphasizes durable materials, secure retention, and an integrated venting mechanism to keep tanks functioning safely under normal pressure changes.\u003c\/p\u003e\n\n\u003ch3\u003eHow does the FSS-377 prevent unauthorized fuel access?\u003c\/h3\u003e\n\u003cp\u003eThe FSS-377 uses a heavy-duty, case-hardened carbon steel cap and adapter that lock together with a user-supplied 5\/16\" shackle padlock, creating a tamper-resistant barrier. CNC machining ensures a precise, tight fit that resists prying and drilling.\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003eCase-hardened carbon steel construction resists cutting and drilling.\u003c\/li\u003e\n  \u003cli\u003eCNC-machined parts for consistent locking engagement.\u003c\/li\u003e\n  \u003cli\u003eAccepts standard 5\/16\" shackle padlocks (not included) for flexible security options.\u003c\/li\u003e\n  \u003cli\u003eInternal gasket seals tank contents to reduce spills during normal use.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eWill it fit my tank and how is it installed?\u003c\/h3\u003e\n\u003cp\u003eThe FSS-377 is made to thread onto any tank with a 2\" male standard thread. Installation is straightforward: attach the adapter to the tank with a wrench and secure the cap with a padlock. For a permanent fit, a thread locker can be applied to the adapter threads.\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003eCompatibility: all 2\" male threaded tanks.\u003c\/li\u003e\n  \u003cli\u003eAdapter installs with a standard wrench; no special tools required.\u003c\/li\u003e\n  \u003cli\u003eOptional thread locker for permanent installation.\u003c\/li\u003e\n  \u003cli\u003eCap attaches to adapter and is locked with a 5\/16\" shackle padlock.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eDoes the cap allow tanks to vent and avoid pressure issues?\u003c\/h3\u003e\n\u003cp\u003eYes. The FSS-377 includes a built-in valve that equalizes pressure and vacuum to protect tank integrity. The valve opens at specific thresholds to vent pressure or relieve vacuum without compromising security.\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003eVent opens at approximately 1.5 psi to relieve excess pressure.\u003c\/li\u003e\n  \u003cli\u003eVacuum relief activates at about 1.5 oz to prevent tank collapse.\u003c\/li\u003e\n  \u003cli\u003eDesigned to minimize spillage; brief venting may allow small amounts of overflow.\u003c\/li\u003e\n  \u003cli\u003eValve is integrated into the cap for continuous protection while locked.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eWhat durability and convenience features does it offer?\u003c\/h3\u003e\n\u003cp\u003eThe FSS-377 is engineered for heavy-duty, long-term service with components that resist wear and vandalism. Practical touches like a removable stainless steel retaining chain and an interior sealing gasket improve daily usability during fueling.\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003eCNC-machined carbon steel for long service life and consistent fit.\u003c\/li\u003e\n  \u003cli\u003e10\" stainless steel retaining chain keeps the cap nearby during refueling and is removable for oversized nozzles.\u003c\/li\u003e\n  \u003cli\u003eInterior gasket seals tank contents and reduces spills between fills.\u003c\/li\u003e\n  \u003cli\u003eHardening treatment improves resistance to damage and tampering attempts.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003cp\u003eWho is this for: The FSS-377 is intended for businesses and individuals responsible for mobile fuel transfer tanks, construction sites, agricultural operations, and commercial above-ground storage where fuel theft, siphoning, or vandalism is a risk. It suits anyone who needs a rugged, threaded locking cap that balances theft protection with necessary venting and everyday practicality.\u003c\/p\u003e\n\u003csection class=\"product-faq-snippet\"\u003e\u003ch3\u003eFAQ\u003c\/h3\u003e\n\u003cdiv class=\"faq-item\"\u003e\n\u003cp class=\"faq-q\"\u003eQ: Does the FSS-377 fit my 2\" threaded tank?\u003c\/p\u003e\n\u003cp class=\"faq-a\"\u003eA: Yes. The FSS-377 is designed for standard 2\" male threaded tanks and installs with a wrench.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"faq-item\"\u003e\n\u003cp class=\"faq-q\"\u003eQ: Can the cap vent pressure while locked?\u003c\/p\u003e\n\u003cp class=\"faq-a\"\u003eA: Yes. An internal valve vents at ~1.5 psi and relieves vacuum at ~1.5 oz while maintaining security.\u003c\/p\u003e\n\u003c\/div\u003e\u003c\/section\u003e","brand":"Flow Security Systems","offers":[{"title":"Default Title","offer_id":55169120567639,"sku":"B0CMVM9Z87","price":83.85,"currency_code":"GBP","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/1050\/1524\/7191\/files\/flow-fss377-front-view.jpg?v=1790418877","url":"https:\/\/britishgarage.co.uk\/products\/flow-security-systems-vented-locking-fuel-tank-cap-2-male-thread-hardened-steel-lock-built-in-vent","provider":"British Garage","version":"1.0","type":"link"}