{"product_id":"mr-o-ring-323-viton-o-ring-90a-1-5-16-in-id-pack-of-25","title":"Mr O-Ring 323 Viton O-Ring 90A - 1-5\/16 in ID, Pack of 25","description":"\u003cp\u003eIn this review the Mr O-Ring 323 Viton O-Ring is assessed for mechanics, fabricators and maintenance buyers who need a small, high-temperature seal in quantity. The bottom line: this pack of 25 provides consistent, high-hardness Viton (FKM) seals rated to 232C\/450F that stand up to fuels, oils and harsh environments, making it a practical choice when durability and chemical resistance matter. The review focuses on real-world sealing uses, material performance and whether the listed nominal and actual dimensions match typical installation needs.\u003c\/p\u003e\n\u003ch2\u003eKey Features\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eMaterial:\u003c\/strong\u003e Viton FKM construction gives reliable resistance to fuels, mineral oils and many organic solvents for longer seal life.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eHardness:\u003c\/strong\u003e The 90A durometer offers a firm seal suitable for static and some dynamic applications where a harder cross-section reduces extrusion.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eTemperature range:\u003c\/strong\u003e Rated from -26C to 232C (-15F to 450F), it handles very high temperature air and many high-heat operating environments.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePack size:\u003c\/strong\u003e Supplied as a pack of 25, useful for workshops or repeat maintenance jobs without frequent reordering.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eSize accuracy:\u003c\/strong\u003e Nominal AS568 sizing provided with actual dimensions, which helps installers verify fit before assembly.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eChemical compatibility:\u003c\/strong\u003e Performs well with petroleum, diesel, biodiesel blends, methanol\/ethanol blends, silicone greases and some strong acids for versatile use.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch2\u003eWho It's For\u003c\/h2\u003e\n\u003cp\u003eThese o-rings suit technicians, marine mechanics, and industrial maintenance staff who need compact, high-temperature resistant seals in bulk. The 90A hardness and Viton chemistry are especially appropriate for fuel systems, hydraulic fixtures where mineral oils or fuels are present, and equipment exposed to ozone and weather.\u003c\/p\u003e\n\u003cp\u003eThose needing very soft or low-friction seals for delicate dynamic shafts should look elsewhere; silicone or nitrile in lower durometers may be a better fit. Also, if a specific non-Viton chemical compatibility is required (for example, concentrated ketones not listed), verify compatibility before use.\u003c\/p\u003e\n\u003ch2\u003ePros \u0026amp; Cons\u003c\/h2\u003e\n\u003cp\u003e\u003cstrong\u003ePros\u003c\/strong\u003e\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003eExcellent high-temperature tolerance up to 232C for demanding applications.\u003c\/li\u003e\n\u003cli\u003eStrong chemical resistance to fuels, oils and many organic solvents increases service life in harsh fluids.\u003c\/li\u003e\n\u003cli\u003ePack of 25 provides convenience and spare parts economy for routine maintenance.\u003c\/li\u003e\n\u003cli\u003eActual dimensions are listed so users can confirm fit against existing grooves and parts.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cstrong\u003eCons\u003c\/strong\u003e\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003eAt 90A hardness the o-ring is relatively firm and may not seal as well on very low-compression or irregular surfaces.\u003c\/li\u003e\n\u003cli\u003eViton is a premium material and can cost more than general-purpose nitrile for noncritical uses.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch2\u003eSpecifications\u003c\/h2\u003e\n\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\u003e1-5\/16 in ID, 1-11\/16 in OD, 3\/16 in CS\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eActual dimensions\u003c\/td\u003e\n\u003ctd\u003e1.287 in ID, 1.707 in OD, 0.210 in CS\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eMetric dimensions\u003c\/td\u003e\n\u003ctd\u003e32.69 mm ID, 43.35 mm OD, 5.33 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\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/table\u003e\n\u003ch2\u003eOur Verdict\u003c\/h2\u003e\n\u003cp\u003eThe Mr O-Ring 323 Viton 90A in a 25-pack is a solid value for professionals who need durable, chemical-resistant seals that tolerate high heat. It is especially useful where fuel and oil exposure is routine and where consistent dimensions matter for fast maintenance. For low-pressure, ultra-soft sealing needs or cost-sensitive noncritical spares, a different material may be preferable.\u003c\/p\u003e\n\u003ch2\u003eFrequently Asked Questions\u003c\/h2\u003e\n\u003cp\u003e\u003cstrong\u003eAre these o-rings compatible with gasoline and diesel?\u003c\/strong\u003e\u003cbr\u003eYes, Viton FKM is compatible with petroleum fuels, diesel and many fuel blends listed in the product information.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWill the 90A hardness work on a dynamic shaft seal?\u003c\/strong\u003e\u003cbr\u003e90A is relatively firm and can work in some dynamic applications, but for low-friction dynamic shafts a softer durometer may seal more effectively.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eDo the nominal and actual dimensions differ significantly?\u003c\/strong\u003e\u003cbr\u003eThe listing provides both nominal AS568-style dimensions and measured actual values so installers can confirm fit before installation.\u003c\/p\u003e","brand":"Mr O-Ring","offers":[{"title":"Default Title","offer_id":48639838683355,"sku":"B07R743PLY","price":43.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0724\/1043\/1707\/files\/51Kuv29LevL._SL1000_ffeddf5c-a1ce-43af-a255-51edd55da8ec.jpg?v=1778572701","url":"https:\/\/gearmusthave.com\/products\/mr-o-ring-323-viton-o-ring-90a-1-5-16-in-id-pack-of-25","provider":"GearMustHave","version":"1.0","type":"link"}