{"product_id":"flow-security-systems-locking-vented-fuel-tank-cap-fss-377-2-male-thread-hardened-carbon-steel-pressure-equalizing-vent","title":"Flow Security Systems locking vented fuel tank cap FSS-377 — 2\" male thread, hardened carbon steel, pressure-equalizing vent","description":"\u003cstrong\u003eThe Flow Security Systems FSS-377 is a hardened, vented locking fuel cap that secures 2\" male-threaded transfer and above-ground commercial tanks against theft, tampering, and siphoning.\u003c\/strong\u003e\n\n\u003cp\u003eDesigned for fleet, construction, agricultural and commercial fueling applications, the FSS-377 combines mechanical strength with a pressure-equalizing valve to protect stored fuel while allowing safe venting. CNC-machined carbon steel components and a case-hardened finish provide resistance to forced entry and wear. The cap fastens to a threaded adapter and uses a standard 5\/16\" shackle padlock (not included) to lock, while an internal gasket and retaining chain control spills and keep the cap accessible during refueling.\u003c\/p\u003e\n\n\u003ch3\u003eHow does the FSS-377 stop fuel theft and tampering?\u003c\/h3\u003e\n\u003cp\u003eThe cap replaces standard non-locking covers with a robust, lockable steel assembly that resists drilling and brute force. Locking the cap to the adapter prevents unauthorized removal, and the solid construction makes siphoning and tampering far more difficult.\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003eCase-hardened carbon steel resists drilling and cutting attempts\u003c\/li\u003e\n  \u003cli\u003eUses any 5\/16\" shackle padlock to secure cap to adapter\u003c\/li\u003e\n  \u003cli\u003eAdapter threads into tank and can be permanently fixed with thread locker\u003c\/li\u003e\n  \u003cli\u003eRetaining chain prevents cap loss during fueling operations\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eWill the venting feature affect tank performance or cause spills?\u003c\/h3\u003e\n\u003cp\u003eThe FSS-377 includes a built-in relief valve to equalize pressure and vacuum at controlled setpoints, helping prevent tank deformation or siphoning-related vacuum issues. Although the gasket seals the opening, brief venting at set pressures can release a small amount of vapors or fluid under extreme conditions; routine operation should not produce noticeable spillage.\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003eValve opens to vent pressure at approximately 1.5 psi\u003c\/li\u003e\n  \u003cli\u003eVacuum release set to about 1.5 oz to prevent tank collapse\u003c\/li\u003e\n  \u003cli\u003eInternal gasket reduces leakage and controls drips\u003c\/li\u003e\n  \u003cli\u003e10\" stainless steel chain holds cap during fills and is removable if needed\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eWhich tanks and locks are compatible with this cap?\u003c\/h3\u003e\n\u003cp\u003eThe FSS-377 is engineered to fit any tank with a 2\" male standard thread, making it suitable for many transfer and above-ground commercial fuel tanks. The cap secures through a simple shackle padlock connection, so you can use widely available 5\/16\" shackle padlocks from your preferred security brand.\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003eFits standard 2\" male threaded tank openings\u003c\/li\u003e\n  \u003cli\u003eAccepts any padlock with a 5\/16\" diameter shackle\u003c\/li\u003e\n  \u003cli\u003eAdapter installs with a wrench for a tight, leak-resistant fit\u003c\/li\u003e\n  \u003cli\u003eThread locker can be applied for permanent installation\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eHow durable is the FSS-377 for field and commercial use?\u003c\/h3\u003e\n\u003cp\u003eBuilt for continuous, heavy-duty service, the cap and adapter are CNC machined from high-quality carbon steel and case-hardened to increase surface hardness and longevity. These manufacturing choices reduce wear from repeated use and increase resistance to common attack methods used by fuel thieves.\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003eHigh-grade carbon steel construction for structural strength\u003c\/li\u003e\n  \u003cli\u003eCNC machining ensures precise fit and smooth operation\u003c\/li\u003e\n  \u003cli\u003eCase-hardening improves resistance to cutting and drilling\u003c\/li\u003e\n  \u003cli\u003eStainless steel retention chain provides corrosion resistance\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003cp\u003eWho this is for: the FSS-377 is intended for fleet managers, site supervisors, equipment owners and anyone responsible for safeguarding stored fuel on mobile transfer tanks or above-ground commercial tanks. If you need a straightforward, heavy-duty locking solution for a 2\" male-threaded tank that vents safely and withstands regular field use, the Flow Security Systems FSS-377 offers a durable, easy-to-fit option.\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 tank?\u003c\/p\u003e\n\u003cp class=\"faq-a\"\u003eA: If your tank has a standard 2\" male thread, the FSS-377 will fit. The adapter installs with a wrench and can be sealed with thread locker.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"faq-item\"\u003e\n\u003cp class=\"faq-q\"\u003eQ: Is a padlock included with the cap?\u003c\/p\u003e\n\u003cp class=\"faq-a\"\u003eA: No — the cap accepts any padlock with a 5\/16\" shackle; choose a weatherproof padlock for outdoor tanks.\u003c\/p\u003e\n\u003c\/div\u003e\u003c\/section\u003e","brand":"Flow Security Systems","offers":[{"title":"Default Title","offer_id":48080898162846,"sku":"B0CMVM9Z87","price":79.93,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0781\/2041\/9486\/files\/flow-security-systems-front-view-cap-installed.jpg?v=1785791784","url":"https:\/\/northtrailauto.ca\/products\/flow-security-systems-locking-vented-fuel-tank-cap-fss-377-2-male-thread-hardened-carbon-steel-pressure-equalizing-vent","provider":"North Trail Auto","version":"1.0","type":"link"}