{"product_id":"mr-o-ring-245-viton-o-ring-90a-durometer-4-3-8-in-id-pack-of-10","title":"Mr O-Ring 245 Viton O-Ring 90A Durometer, 4-3\/8 in ID (Pack of 10)","description":"\u003cp\u003eIn this review the Mr O-Ring 245 Viton O-Ring is evaluated for technicians, maintenance pros and hobbyists who need a heat- and chemical-resistant seal in repeatable sizes. The bottom line: this pack of ten 90A durometer Viton o-rings is best for applications exposed to high temperatures, fuels or aggressive fluids because its fluorocarbon compound withstands up to 232C and resists petroleum, diesel, biodiesel blends and many solvents. The review focuses on fit, material performance and typical use cases where the combination of the 4-3\/8 in nominal inner diameter and the 1\/8 in cross-section matter most.\u003c\/p\u003e\n\n\u003ch2\u003eKey Features\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eMaterial:\u003c\/strong\u003e The Viton (FKM) compound provides outstanding resistance to high temperature, ozone and a wide range of chemicals, making these o-rings suitable for harsh environments.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eTemperature range:\u003c\/strong\u003e Rated from -26C (-15F) to 232C (450F), they hold seals under high heat and low temperature service without rapid degradation.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eSize accuracy:\u003c\/strong\u003e Nominal and actual dimensions are closely matched (4-3\/8 in nominal ID, actual 4.359 in ID) so repeatable fit is achieved for parts designed to AS568 size equivalents.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDurometer:\u003c\/strong\u003e The 90A hardness gives a firmer seal for static and some dynamic applications where compression set and extrusion resistance are priorities.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePack quantity:\u003c\/strong\u003e Sold as a pack of 10, the set provides spare parts for routine maintenance or multiple assemblies without needing to reorder frequently.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eVersatility:\u003c\/strong\u003e Performs well with petroleum, diesel, biodiesel blends, methanol\/ethanol blends, silicone oils and in high vacuum applications, expanding usable service scenarios.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eWho It's For\u003c\/h2\u003e\n\u003cp\u003eThis o-ring pack is aimed at maintenance engineers, industrial mechanics and DIYers who work with fuel systems, hydraulic components, pumps or ovens where high temperature resistance and chemical compatibility are required. The 90A hardness and Viton formulation make it especially useful when exposure to mineral oils, fuels and aromatic solvents is expected.\u003c\/p\u003e\n\u003cp\u003eThose who need softer, more flexible seals for low-pressure static sealing or very tight dynamic rotary seals might prefer a lower durometer or a different elastomer. If you need metric-size inventory or very soft rubber for cushioning, this specific 90A Viton with 1\/8 in cross-section is not the ideal choice.\u003c\/p\u003e\n\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 chemical and temperature resistance due to the fluorocarbon Viton compound.\u003c\/li\u003e\n\u003cli\u003eAccurate actual dimensions (4.359 in ID, 4.637 in OD, 0.139 in CS) for predictable fit in AS568-equivalent housings.\u003c\/li\u003e\n\u003cli\u003e90A durometer delivers good extrusion resistance and durability in demanding service.\u003c\/li\u003e\n\u003cli\u003ePack of 10 provides convenient spares for maintenance cycles.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cstrong\u003eCons\u003c\/strong\u003e\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e90A hardness may be too stiff for applications requiring very soft or highly conforming seals.\u003c\/li\u003e\n\u003cli\u003eNot specified for specialty chemicals outside the common solvents and fuels listed, so verify compatibility for unusual media.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eSpecifications\u003c\/h2\u003e\n\u003ctable\u003e\n\u003ctr\u003e\n\u003ctd\u003eMaterial\u003c\/td\u003e\n\u003ctd\u003eViton (FKM) fluorocarbon rubber\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\u003e4-3\/8 in ID, 4-5\/8 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\u003e4.359 in ID, 4.637 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\u003e110.72 mm ID, 117.78 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\u003e10 o-rings\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/table\u003e\n\n\u003ch2\u003eOur Verdict\u003c\/h2\u003e\n\u003cp\u003eFor anyone needing a durable, heat- and chemical-resistant seal in a common AS568-equivalent size, this 245 Viton 90A o-ring pack is a reliable, cost-effective choice. It delivers accurate sizing, broad fluid compatibility and long service life for fuel, oil and high-temperature applications, though those needing softer seals should consider a lower durometer alternative.\u003c\/p\u003e\n\n\u003ch2\u003eFrequently Asked Questions\u003c\/h2\u003e\n\u003cp\u003e\u003cstrong\u003eAre these o-rings compatible with diesel and biodiesel?\u003c\/strong\u003e\u003cbr\u003eYes, the Viton compound is rated for petroleum products including diesel and blends with biodiesel as noted in the product description.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWill the 90A hardness work for dynamic seals?\u003c\/strong\u003e\u003cbr\u003e90A can be used for some dynamic applications but is firmer; verify movement, speed and extrusion gaps before selecting for rotary shafts.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eDo these match AS568 sizes?\u003c\/strong\u003e\u003cbr\u003eThe o-rings are offered to meet AS568-defined sizes and the actual dimensions are provided to confirm fit.\u003c\/p\u003e","brand":"Mr O-Ring","offers":[{"title":"Default Title","offer_id":48179768230107,"sku":"B07R73QZVS","price":36.29,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0724\/1043\/1707\/files\/51Kuv29LevL._SL1000_5e378557-9e92-4ae4-b6f4-912ca4ab6350.jpg?v=1769606900","url":"https:\/\/gearmusthave.com\/products\/mr-o-ring-245-viton-o-ring-90a-durometer-4-3-8-in-id-pack-of-10","provider":"GearMustHave","version":"1.0","type":"link"}