{"product_id":"mr-o-ring-240-viton-o-ring-3-3-4-in-id-4-in-od-pack-of-25","title":"Mr O-Ring 240 Viton O-Ring 3-3\/4 in ID 4 in OD - Pack of 25","description":"\u003cp\u003eIn this review the focus is on a workhorse sealing part: the \u003cstrong\u003e240 Viton O-Ring\u003c\/strong\u003e in a pack of 25. The bottom line is simple - this kit is aimed at technicians, mechanics and maintenance crews who need reliable, high-temperature resistant seals in common AS568 sizes. The reviewer found the material and dimensions match typical industrial expectations, and the long temperature range and chemical compatibility make these o-rings a straightforward choice when replacing seals exposed to fuels, oils or high heat.\u003c\/p\u003e\u003ch2\u003eKey Features\u003c\/h2\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eMaterial:\u003c\/strong\u003e Made from Viton (FKM), these o-rings resist high temperatures and a wide range of chemicals, which keeps seals intact under demanding service conditions.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDurometer:\u003c\/strong\u003e The 90A hardness provides a durable, firm seal that holds shape under compression and performs well in static and some dynamic applications.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePack size:\u003c\/strong\u003e Supplied as a pack of 25, the quantity is useful for routine maintenance and stocking common replacement parts on the shop shelf.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eTemperature range:\u003c\/strong\u003e Rated from -26C (-15F) to 232C (450F), the rings cover both low-temperature starts and sustained high-heat operation without rapid degradation.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDimensional accuracy:\u003c\/strong\u003e Nominal and measured dimensions are close (3-3\/4 in ID nominal; actual 3.734 in ID and 4.012 in OD), which helps when matching to AS568 size standards.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eChemical compatibility:\u003c\/strong\u003e Performs well with petroleum products, fuels, biodiesel blends, mineral and silicone oils, and resists ozone and weathering for outdoor or exposed use.\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch2\u003eWho It's For\u003c\/h2\u003e\u003cp\u003eThis product is best for industrial maintenance, plumbing and hydraulic technicians who need a reliable, heat-resistant o-ring in a common AS568 size. The pack of 25 makes it practical for on-site repairs, scheduled maintenance, and stocking in a parts cabinet for repeat service needs.\u003c\/p\u003e\u003cp\u003eThose who need extreme low-temperature flexibility, very soft sealing material for delicate dynamic shafts, or custom compound formulations for specialty chemicals should look elsewhere. For general-purpose high-temp and fuel-exposed sealing, these Viton o-rings are a sensible choice.\u003c\/p\u003e\u003ch2\u003ePros \u0026amp; Cons\u003c\/h2\u003e\u003cp\u003e\u003cstrong\u003ePros\u003c\/strong\u003e\u003c\/p\u003e\u003cul\u003e\n\u003cli\u003eHigh temperature and chemical resistance from the Viton (FKM) compound gives long service life in fuel and oil environments.\u003c\/li\u003e\n\u003cli\u003e90A durometer provides a robust seal that maintains shape and compression for many static applications.\u003c\/li\u003e\n\u003cli\u003ePack of 25 is convenient for maintenance teams and reduces the need for frequent reordering.\u003c\/li\u003e\n\u003c\/ul\u003e\u003cp\u003e\u003cstrong\u003eCons\u003c\/strong\u003e\u003c\/p\u003e\u003cul\u003e\u003cli\u003eHigher durometer means the rings are firmer; they may not be ideal for very low-pressure or delicate dynamic sealing where a softer material is preferred.\u003c\/li\u003e\u003c\/ul\u003e\u003ch2\u003eSpecifications\u003c\/h2\u003e\u003ctable\u003e\n\u003ctr\u003e\n\u003ctd\u003eMaterial\u003c\/td\u003e\n\u003ctd\u003eViton (FKM)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eDurometer\u003c\/td\u003e\n\u003ctd\u003e90A\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eNominal dimensions\u003c\/td\u003e\n\u003ctd\u003e3-3\/4 in ID, 4 in OD, 1\/8 in CS\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eActual dimensions\u003c\/td\u003e\n\u003ctd\u003e3.734 in ID, 4.012 in OD, 0.139 in CS\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eMetric dimensions\u003c\/td\u003e\n\u003ctd\u003e94.84 mm ID, 101.90 mm OD, 3.53 mm CS\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTemperature range\u003c\/td\u003e\n\u003ctd\u003e-26C (-15F) to 232C (450F)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003ePack quantity\u003c\/td\u003e\n\u003ctd\u003e25 rings\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/table\u003e\u003ch2\u003eOur Verdict\u003c\/h2\u003e\u003cp\u003eThe Mr O-Ring 240 Viton pack of 25 is a practical, value-oriented choice for technicians who need dependable, high-temperature and fuel-resistant seals in a common AS568 size. It is especially good for static sealing and routine maintenance stocking; those needing softer compounds for delicate dynamic seals should consider alternative materials.\u003c\/p\u003e\u003ch2\u003eFrequently Asked Questions\u003c\/h2\u003e\u003cp\u003e\u003cstrong\u003eAre these o-rings compatible with gasoline and diesel?\u003c\/strong\u003e\u003cbr\u003eYes. The Viton compound is compatible with petroleum fuels, diesel and common fuel blends including biodiesel and methanol\/ethanol blends.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eDo the dimensions match AS568 sizing?\u003c\/strong\u003e\u003cbr\u003eYes. The product is offered to meet AS568 size standards and the actual measurements closely match the nominal 3-3\/4 in ID specification.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eCan these be used for high-temperature applications?\u003c\/strong\u003e\u003cbr\u003eYes. The rings are rated to 232C (450F), making them suitable for many high-heat sealing situations.\u003c\/p\u003e","brand":"Mr O-Ring","offers":[{"title":"Default Title","offer_id":48177890164955,"sku":"B07R62T8S3","price":59.39,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0724\/1043\/1707\/files\/51Kuv29LevL._SL1000_9dda2d3c-d783-4fd3-9e07-15a638f72b36.jpg?v=1769444926","url":"https:\/\/gearmusthave.com\/products\/mr-o-ring-240-viton-o-ring-3-3-4-in-id-4-in-od-pack-of-25","provider":"GearMustHave","version":"1.0","type":"link"}