{"product_id":"045-o-ring-buna-n-90a-4in-id-4-1-8in-od-1-16in-width-pack-of-100","title":"045 O-Ring Buna-N 90A 4in ID 4-1\/8in OD 1\/16in Width Pack of 100","description":"\u003cp\u003eIn this review the 045 O-Ring in black Buna-nitrile is evaluated for technicians, hobbyists, and anyone who needs a batch of tough, standard-size seals. The bottom line: buy this pack if you need consistent, industrial-spec O-rings that meet Aerospace Standard AS568A and resist petroleum-based fluids. The reviewer found the 90A durometer results in a noticeably stiff ring that holds shape and seals reliably, making it especially useful where durability and chemical compatibility with oils and hydrocarbons are required.\u003c\/p\u003e\n\u003ch2\u003eKey Features\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eMaterial:\u003c\/strong\u003e Buna-nitrile construction provides broad compatibility with petroleum, HFCs, vegetable oils and alcohols for common sealing tasks.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eHardness:\u003c\/strong\u003e 90A durometer gives a firm, abrasion-resistant seal that resists extrusion in moderate-pressure couplings.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eSize accuracy:\u003c\/strong\u003e AS568A Aerospace sizing ensures these rings match standard 045 grooves and fittings for predictable fit.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eTemperature range:\u003c\/strong\u003e Usable from -40 degrees F to 212 degrees F so it performs in cold storage and typical engine or hydraulic environments.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCross-section:\u003c\/strong\u003e Round profile creates a reliable seal between overlapping cylindrical surfaces and quick disconnects.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePack quantity:\u003c\/strong\u003e Supplied as a bulk pack of 100, making it convenient for maintenance shops, fleets, or repetitive DIY projects.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch2\u003eWho It's For\u003c\/h2\u003e\n\u003cp\u003eThis O-ring pack is aimed at maintenance professionals, small repair shops, and DIYers who work with garden hose quick disconnects, hydraulic couplers, or marine fittings and need dozens of identical, tough seals. The firm 90A hardness and Buna-N compatibility make it a practical choice where petroleum resistance and abrasion strength matter.\u003c\/p\u003e\n\u003cp\u003eThose who need extreme flexibility at very low temperatures, high resistance to ketones or ozone, or softer seals for delicate instrumentation should look elsewhere, since Buna-nitrile is vulnerable to acetone, ethers, esters and ozone and the 90A hardness is relatively stiff compared with softer 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\u003eMeets AS568A sizing so rings fit standard 045 grooves without trimming.\u003c\/li\u003e\n\u003cli\u003eBuna-N compound balances oil and fuel compatibility with abrasion and tear resistance.\u003c\/li\u003e\n\u003cli\u003eBulk pack of 100 delivers good value for routine maintenance and multi-unit repairs.\u003c\/li\u003e\n\u003cli\u003eWide usable temperature range covers most workshop and outdoor applications.\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 feels stiff to some users and can be rigid like hard plastic in hand.\u003c\/li\u003e\n\u003cli\u003eNot compatible with acetone, ethers, esters, ozone or prolonged sunlight exposure, limiting some chemical applications.\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\u003eBuna-nitrile (Buna-N)\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\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\u003e4-1\/8 in\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCross-section Width\u003c\/td\u003e\n\u003ctd\u003e1\/16 in\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\u003eStandards\u003c\/td\u003e\n\u003ctd\u003eMeets Aerospace Standard AS568A\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/table\u003e\n\u003ch2\u003eOur Verdict\u003c\/h2\u003e\n\u003cp\u003eThe 045 O-Ring in Buna-N 90A is a solid, cost-effective choice for anyone needing many consistent, oil-resistant seals. Its firm hardness and AS568A sizing mean reliable fit and long service in common hydraulic, plumbing and outdoor equipment, making it good value for workshops and fleet maintenance where chemical exposure stays within Buna-N limits.\u003c\/p\u003e\n\u003ch2\u003eFrequently Asked Questions\u003c\/h2\u003e\n\u003cp\u003e\u003cstrong\u003eWill these O-rings fit standard 045 grooves?\u003c\/strong\u003e\u003cbr\u003eYes. They are manufactured to AS568A sizing for the 045 O-ring, so they are intended to fit standard 045 grooves and fittings.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eAre these O-rings suitable for fuel and oil?\u003c\/strong\u003e\u003cbr\u003eYes. Buna-nitrile is compatible with petroleum, HFCs and many hydrocarbons, making these O-rings suitable for fuel- and oil-exposed applications.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eDo they stay flexible in cold weather?\u003c\/strong\u003e\u003cbr\u003eThey are usable down to -40 degrees F, but the 90A hardness makes them relatively stiff compared with softer compounds at low temperatures.\u003c\/p\u003e","brand":"Mr O-Ring","offers":[{"title":"Default Title","offer_id":48632743624923,"sku":"B00M90A1L2","price":32.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0724\/1043\/1707\/files\/514anOq3sCL._SL1224_bed70bc7-623a-4033-af82-1797573b2435.jpg?v=1778485974","url":"https:\/\/gearmusthave.com\/products\/045-o-ring-buna-n-90a-4in-id-4-1-8in-od-1-16in-width-pack-of-100","provider":"GearMustHave","version":"1.0","type":"link"}