{"product_id":"mr-o-ring-348-viton-o-ring-4-3-8-in-id-pack-of-25-high-temp-seal","title":"Mr O-Ring 348 Viton O-Ring 4-3\/8 in ID Pack of 25 - High Temp Seal","description":"\u003cp\u003eIn this review the Mr O-Ring 348 Viton o-ring pack is evaluated for technicians, maintenance pros and DIYers who need a reliable sealing solution for high temperature or fuel-exposed systems. The bottom line: this 90A durometer Viton o-ring stands out for its temperature range and chemical resistance, making it a practical choice where mineral oils, fuels, silicone oils, ozone or weather exposure are expected. The pack of 25 covers repeated service needs and the o-ring sizes adhere to AS568 standards, so replacements and inventory management are straightforward for workshops and field crews.\u003c\/p\u003e\n\u003ch2\u003eKey Features\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eMaterial:\u003c\/strong\u003e Made from Viton (FKM), the rubber offers strong resistance to high temperature and many chemicals encountered in industrial service.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDurometer:\u003c\/strong\u003e The 90A hardness gives a firm sealing surface that resists extrusion while still providing reliable compression sealing.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDimensions:\u003c\/strong\u003e Nominal 4-3\/8 in ID and 4-3\/4 in OD with actual 4.350 in ID and 4.770 in OD, which helps ensure an accurate fit in AS568 applications.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eTemperature range:\u003c\/strong\u003e Rated from -26C (-15F) to 232C (450F), suitable for very high temperature air and hot fluid environments.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eChemical compatibility:\u003c\/strong\u003e Performs well with petroleum products, fuels, biodiesel blends, methanol or ethanol blends, mineral and silicone oils and many solvents.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePack size:\u003c\/strong\u003e Supplied in a pack of 25, which is convenient for repeated maintenance cycles or stocking in a service shop.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch2\u003eWho It's For\u003c\/h2\u003e\n\u003cp\u003eThe Mr O-Ring 348 Viton is best for maintenance technicians, mechanics and HVAC or hydraulic specialists who require durable seals that tolerate high temperatures and exposure to fuels and oils. It is also useful for manufacturers and fabricators who maintain equipment with AS568 size requirements and prefer bulk packs for inventory.\u003c\/p\u003e\n\u003cp\u003eThose who need extremely soft, low-durometer seals for delicate pneumatic systems or who require elastomers designed for prolonged exposure to strong caustics should look elsewhere; Viton is optimized for heat and hydrocarbon resistance rather than the soft sealing feel of low-hardness elastomers.\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 stability and broad chemical resistance for fuel- and oil-exposed systems.\u003c\/li\u003e\n\u003cli\u003e90A hardness resists extrusion and provides a reliable compression seal in demanding applications.\u003c\/li\u003e\n\u003cli\u003ePack of 25 makes it easy to service multiple units and keep spare inventory on hand.\u003c\/li\u003e\n\u003cli\u003eActual and metric dimensions are provided, aiding correct selection and installation.\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 durometer the o-ring is relatively firm, which may not be ideal where a softer compressible seal is required.\u003c\/li\u003e\n\u003cli\u003eViton is less suited for prolonged exposure to certain strong caustic solutions, so chemical compatibility should be confirmed for specific fluids.\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\u003e4-3\/8 in ID, 4-3\/4 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\u003e4.350 in ID, 4.770 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\u003e110.49 mm ID, 121.15 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 size\u003c\/td\u003e\n\u003ctd\u003e25 pieces\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/table\u003e\n\u003ch2\u003eOur Verdict\u003c\/h2\u003e\n\u003cp\u003eThe Mr O-Ring 348 Viton 90A pack is a solid, cost-effective choice for professionals who need dependable seals that resist heat, fuels and oils. Its AS568 sizing, clear actual dimensions and bulk pack format deliver good value for workshops and field service; choose a softer elastomer only if your application specifically requires lower durometer material.\u003c\/p\u003e\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 material is formulated to perform well with diesel and blends containing biodiesel as listed in the product details.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eDo the dimensions follow a standard size?\u003c\/strong\u003e\u003cbr\u003eYes, these o-rings meet AS568 size standards and the listing includes both nominal and actual dimensions to confirm fit.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWhat environments are unsuitable for Viton?\u003c\/strong\u003e\u003cbr\u003eViton is not ideal for prolonged exposure to strong caustic solutions or environments demanding very soft, low-durometer sealing surfaces.\u003c\/p\u003e","brand":"Mr O-Ring","offers":[{"title":"Default Title","offer_id":48241926111451,"sku":"B07R73CRFP","price":128.69,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0724\/1043\/1707\/files\/51Kuv29LevL._SL1000_35ba4cb6-d9b7-4444-b6c9-5db127fdf081.jpg?v=1771087943","url":"https:\/\/gearmusthave.com\/products\/mr-o-ring-348-viton-o-ring-4-3-8-in-id-pack-of-25-high-temp-seal","provider":"GearMustHave","version":"1.0","type":"link"}