{"product_id":"mr-o-ring-343-epdm-o-ring-70a-durometer-pack-of-25-durable-seal","title":"Mr O-Ring 343 EPDM O-Ring 70A Durometer Pack of 25 - Durable Seal","description":"\u003cp\u003eIn this review the Mr O-Ring 343 EPDM O-Ring is presented as a practical, no-frills pack of seals for technicians and DIYers who need reliable, weather-resistant o-rings in a common AS568 size. The bottom line: this pack of 25 o-rings offers consistent dimensions and material properties that make it an appealing choice for sealing applications exposed to ozone, steam, water and many polar solvents; the review focuses on real-world use, dimensional accuracy and material performance across temperature extremes.\u003c\/p\u003e\n\n\u003ch2\u003eKey Features\u003c\/h2\u003e\n\u003cul\u003e\n \u003cli\u003e\n\u003cstrong\u003eMaterial:\u003c\/strong\u003e EPDM compound gives strong resistance to ozone, sunlight and weathering so seals last longer in outdoor and exposed applications.\u003c\/li\u003e\n \u003cli\u003e\n\u003cstrong\u003eDurometer:\u003c\/strong\u003e 70A hardness balances flexibility and compression set resistance for general purpose sealing without being too soft or brittle.\u003c\/li\u003e\n \u003cli\u003e\n\u003cstrong\u003eSize accuracy:\u003c\/strong\u003e Nominal and actual dimensions are provided so installers can match the 3-3\/4' ID and 4-1\/8' OD size precisely to AS568 specifications.\u003c\/li\u003e\n \u003cli\u003e\n\u003cstrong\u003eTemperature range:\u003c\/strong\u003e Rated from -55C to 125C, making these o-rings suitable for cold environments and many hot fluid systems below the upper limit.\u003c\/li\u003e\n \u003cli\u003e\n\u003cstrong\u003eChemical compatibility:\u003c\/strong\u003e Performs well with alcohols, brake fluid, dilute acids and alkalis, silicone oils and water, reducing the need for multiple material types.\u003c\/li\u003e\n \u003cli\u003e\n\u003cstrong\u003ePack quantity:\u003c\/strong\u003e Sold as a pack of 25 which is convenient for maintenance spares and repetitive repair tasks.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eWho It's For\u003c\/h2\u003e\n\u003cp\u003eThe 343 EPDM o-ring pack is aimed at maintenance technicians, plumbing and hydraulic repair professionals, and hobbyists who need a reliable general-purpose seal that resists weathering and ozone. It is especially useful where a consistent bulk supply is needed for recurring maintenance jobs or inventory stocking.\u003c\/p\u003e\n\u003cp\u003eThose who need resistance to petroleum-based oils, high-temperature engine oils above 125C, or specific fluorinated chemical compatibility should look at alternative elastomers. Also, applications needing ultra-precise tolerances for specialized dynamic sealing may require a different durometer or compound.\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\u003eGood environmental resistance: EPDM resists ozone, sunlight and weathering for outdoor and exposed use.\u003c\/li\u003e\n \u003cli\u003eClear sizing: actual and nominal dimensions are listed so fitting is straightforward and repeatable.\u003c\/li\u003e\n \u003cli\u003eVersatile chemical compatibility: suitable for alcohols, brake fluid, dilute acids and many polar solvents.\u003c\/li\u003e\n \u003cli\u003eValue pack: 25 pieces provides a cost-effective supply for maintenance and repairs.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cstrong\u003eCons\u003c\/strong\u003e\u003c\/p\u003e\n\u003cul\u003e\n \u003cli\u003eNot suitable for petroleum-based hydraulic fluids and some oils, so compatibility must be checked before use.\u003c\/li\u003e\n \u003cli\u003eUpper temperature limit of 125C may be insufficient for some high-heat applications or continuous steam above rated max.\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\u003eEPDM\u003c\/td\u003e\n\u003c\/tr\u003e\n \u003ctr\u003e\n\u003ctd\u003eDurometer\u003c\/td\u003e\n\u003ctd\u003e70A\u003c\/td\u003e\n\u003c\/tr\u003e\n \u003ctr\u003e\n\u003ctd\u003eNominal dimensions\u003c\/td\u003e\n\u003ctd\u003e3-3\/4' ID, 4-1\/8' OD, 3\/16' CS\u003c\/td\u003e\n\u003c\/tr\u003e\n \u003ctr\u003e\n\u003ctd\u003eActual dimensions\u003c\/td\u003e\n\u003ctd\u003e3.725' ID, 4.145' OD, 0.210' CS\u003c\/td\u003e\n\u003c\/tr\u003e\n \u003ctr\u003e\n\u003ctd\u003eMetric dimensions\u003c\/td\u003e\n\u003ctd\u003e94.62 mm ID, 105.28 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-55C (-67F) to 125C (257F)\u003c\/td\u003e\n\u003c\/tr\u003e\n \u003ctr\u003e\n\u003ctd\u003ePack quantity\u003c\/td\u003e\n\u003ctd\u003e25 pieces\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/table\u003e\n\n\u003ch2\u003eOur Verdict\u003c\/h2\u003e\n\u003cp\u003eThe Mr O-Ring 343 EPDM 70A pack is a solid, cost-effective choice for general sealing where ozone and weather resistance are priorities. For routine maintenance, plumbing and many hydraulic or steam applications within the stated temperature range it offers reliable performance and clear sizing, making it good value for those who need a dependable bulk supply.\u003c\/p\u003e\n\n\u003ch2\u003eFrequently Asked Questions\u003c\/h2\u003e\n\u003cp\u003e\u003cstrong\u003eAre these o-rings suitable for outdoor use?\u003c\/strong\u003e\u003cbr\u003eYes. The EPDM material resists ozone, sunlight and weathering, making these o-rings well suited for outdoor and exposed installations.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eCan I use them with engine oil or petroleum hydraulic fluid?\u003c\/strong\u003e\u003cbr\u003eNo. EPDM is not recommended for petroleum-based oils; use a different elastomer for those fluids to avoid swelling or degradation.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eDo the actual dimensions match AS568 size standards?\u003c\/strong\u003e\u003cbr\u003eYes. The product lists nominal and actual dimensions that align with AS568 sizing for consistent fit in standard grooves.\u003c\/p\u003e","brand":"Mr O-Ring","offers":[{"title":"Default Title","offer_id":48205883572443,"sku":"B07R73BS8N","price":32.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0724\/1043\/1707\/files\/51Kuv29LevL._SL1000_1dc31af9-4ffe-4361-8b0d-a4b9070a3520.jpg?v=1770207485","url":"https:\/\/gearmusthave.com\/products\/mr-o-ring-343-epdm-o-ring-70a-durometer-pack-of-25-durable-seal","provider":"GearMustHave","version":"1.0","type":"link"}