What is an O-Ring?
An O-Ring is a torus-shaped elastomer seal used in static and dynamic sealing applications. It sits in a machined groove (gland) and is compressed between two mating surfaces to prevent fluid or gas leakage.
What is the most common O-Ring material?
NBR (Nitrile) is the most common general-purpose material for mineral oil, petroleum fuels and hydraulic fluids. FKM (Viton-type) is the next most common for higher temperature and chemical resistance.
What is the difference between NBR and FKM?
NBR handles mineral oils and hydraulic fluid to about 100°C. FKM resists higher temperatures (to 200°C) and a far broader chemical range including acids and synthetic fuels, at higher cost. Switch from NBR to FKM when fluid chemistry, temperature or chemical exposure exceeds NBR's limits.
What does 70 Shore A mean?
Shore A measures resistance to surface indentation. 70 Shore A is the standard O-Ring hardness — firm but flexible. 90 Shore A is harder, specified where extrusion resistance matters at higher system pressures.
What is AS568?
AS568 is the American SAE standard for O-Ring sizes, using dash numbers (-001 to -475) to specify ID and cross-section in imperial inches. It is the dominant standard in the US and common globally in oil & gas and aerospace.
How do I measure an O-Ring?
Measure Inside Diameter (ID) and Cross-Section (CS) with calipers on an unstretched ring at room temperature. Outside Diameter (OD) = ID + 2×CS. If the ring has swelled in service, measure the groove instead.
Can FITCO manufacture custom O-Ring sizes?
Yes — any ID and CS combination in all major compounds. Our 2,000+ mold library covers most sizes without new tooling cost. Custom molds are quoted separately with 3–6 week lead time.
What is the minimum order quantity?
Standard NBR and FKM O-Rings typically start from 100–500 pieces. Send your enquiry with size, material and quantity for a confirmed price and MOQ.
Does FITCO ship internationally?
Yes — from India to UAE, Saudi Arabia, Qatar, Oman, Kuwait, UK, Germany, Canada, USA, Singapore, Australia and more. Dubai entity handles GCC clearance. Worldwide shipping by air and sea.