{"product_id":"345-viton-o-ring-75a-4in-id-4-3-8in-od-high-temp-chemical-seal","title":"345 Viton O-Ring 75A 4in ID 4-3\/8in OD - High Temp Chemical Seal","description":"\u003cp\u003eIn this review the 345 Viton O-ring is evaluated as a robust sealing solution for demanding fluid and fuel applications; the main reason to buy is its chemical and temperature resilience. The reviewer found these black, round O-rings especially useful where heat, fuel exposure, or aggressive solvents are present, and notes they arrive as a pack of 100 suitable for repeated replacements. For anyone needing a reliable, AS568A-size replacement with a mid-range hardness, this O-ring delivers consistent fit and long service life.\u003c\/p\u003e\u003ch2\u003eKey Features\u003c\/h2\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eMaterial:\u003c\/strong\u003e Made of Viton fluorocarbon elastomer to resist a wide range of fuels and chemicals for longer seal life.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eTemperature range:\u003c\/strong\u003e Usable from -15 degrees F to 400 degrees F, allowing installation in both cold starts and high-heat systems.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDurometer:\u003c\/strong\u003e 75A hardness gives a balance of compression resistance and flexibility for durable sealing under pressure.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCross-section:\u003c\/strong\u003e Round profile provides a standard, reliable seal between overlapping cylindrical parts and shafts.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eStandards:\u003c\/strong\u003e Sized to meet Aerospace Standard AS568A which ensures common interchangeability in many fittings.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePack quantity:\u003c\/strong\u003e Supplied as a bulk pack of 100, making it economical for maintenance and repeated replacements.\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch2\u003eWho It's For\u003c\/h2\u003e\u003cp\u003eThese O-rings are best for technicians, hobbyists, and maintenance teams working with hydraulic or fuel systems, chemical handling equipment, and vacuum or ozone-exposed assemblies. They suit replacement tasks on items like MSA fuel bottles, barrel seals, and similar cylindrical interfaces where AS568A sizing and chemical resistance matter.\u003c\/p\u003e\u003cp\u003eCustomers who regularly expose seals to low molecular organic acids, ammonia, strong alkalis, or glycol-based brake fluids should look elsewhere; Viton is vulnerable to those media. If a softer elastomer or food-grade approval is required, select a material matched to that specification instead of this 75A Viton.\u003c\/p\u003e\u003ch2\u003ePros \u0026amp; Cons\u003c\/h2\u003e\u003cp\u003e\u003cstrong\u003ePros\u003c\/strong\u003e\u003c\/p\u003e\u003cul\u003e\n\u003cli\u003eExcellent resistance to fuels, aromatic and aliphatic hydrocarbons, and many solvents for reliable performance.\u003c\/li\u003e\n\u003cli\u003eWide usable temperature range from -15 degrees F to 400 degrees F for versatile installations.\u003c\/li\u003e\n\u003cli\u003eGood value supplied in a 100-pack for frequent maintenance or inventory stocking.\u003c\/li\u003e\n\u003cli\u003eMeets AS568A sizing so it fits common standard grooves and fittings without guesswork.\u003c\/li\u003e\n\u003c\/ul\u003e\u003cp\u003e\u003cstrong\u003eCons\u003c\/strong\u003e\u003c\/p\u003e\u003cul\u003e\n\u003cli\u003eNot compatible with low molecular organic acids, ammonia gas, strong alkalis, amines, and glycol-based brake fluids, so chemical compatibility must be checked.\u003c\/li\u003e\n\u003cli\u003e75A hardness may be firmer than desired for some delicate or low-compression applications.\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch2\u003eSpecifications\u003c\/h2\u003e\u003ctable\u003e\n\u003ctr\u003e\n\u003ctd\u003eMaterial\u003c\/td\u003e\n\u003ctd\u003eViton (fluorocarbon elastomer)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eColor\u003c\/td\u003e\n\u003ctd\u003eBlack\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eInner diameter (ID)\u003c\/td\u003e\n\u003ctd\u003e4 in\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eOuter diameter (OD)\u003c\/td\u003e\n\u003ctd\u003e4-3\/8 in\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCross-section \/ Width\u003c\/td\u003e\n\u003ctd\u003e3\/16 in\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eDurometer\u003c\/td\u003e\n\u003ctd\u003e75A\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTemperature range\u003c\/td\u003e\n\u003ctd\u003e-15 degrees F to 400 degrees F\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/table\u003e\u003ch2\u003eOur Verdict\u003c\/h2\u003e\u003cp\u003eThe 345 Viton O-ring is a sensible choice for anyone needing an economical, chemically resistant seal in fuel, solvent, and high-temperature environments; its AS568A sizing and 75A hardness strike a useful balance for many maintenance tasks. Buyers should verify compatibility with specific chemicals like glycol-based fluids or strong alkalis before fitting, but for general fuel and heat exposure this pack of 100 represents solid value and dependable performance.\u003c\/p\u003e\u003ch2\u003eFrequently Asked Questions\u003c\/h2\u003e\u003cp\u003e\u003cstrong\u003eAre these O-rings compatible with fuel?\u003c\/strong\u003e\u003cbr\u003eYes, Viton is compatible with many fuels including aromatic and aliphatic hydrocarbons and works well in non-flammable hydraulic fuels.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat temperature range will they withstand?\u003c\/strong\u003e\u003cbr\u003eThey are rated for use from -15 degrees F up to 400 degrees F, suitable for most heat-exposed seals.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWill they resist brake fluid and ammonia?\u003c\/strong\u003e\u003cbr\u003eNo, Viton is vulnerable to glycol-based brake fluids, ammonia gas, and some strong alkalis, so avoid those fluids.\u003c\/p\u003e","brand":"Mr O-Ring","offers":[{"title":"Default Title","offer_id":48608130203867,"sku":"B000MNBQ1C","price":385.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0724\/1043\/1707\/files\/81iyYJCP7YL._SL1500_4e00949a-edbb-48f3-95a1-b35b49450bb7.jpg?v=1778568297","url":"https:\/\/gearmusthave.com\/products\/345-viton-o-ring-75a-4in-id-4-3-8in-od-high-temp-chemical-seal","provider":"GearMustHave","version":"1.0","type":"link"}