NBR VMQ FKM O-Rings CS 3.5mm OD 51–200mm Rubber Seal Gaskets
NBR VMQ FKM O-Rings CS 3.5mm OD 51–200mm Rubber Seal Gaskets
Details
Ouling NBR / VMQ / FKM O-Rings — 3.5 mm Cross-Section, 51–200 mm OD
Keep your hydraulic, pneumatic, and plumbing systems leak-free with these precision-engineered O-rings from Ouling. Available in three high-performance rubber compounds — Nitrile (NBR), Silicone (VMQ), and Fluorocarbon (FKM/Fluorine) — and in a wide range of outer diameters from 51 mm up to 200 mm, these ring gaskets deliver a reliable, pressure-rated seal in demanding industrial and DIY applications.
Made in Mainland China.
Key Features
- Cross-Section (CS): 3.5 mm — standard ring-gasket profile for consistent sealing
- Outer Diameter (OD): 51 mm – 200 mm range to suit a variety of fittings and housings
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Material Options:
- NBR (Nitrile Rubber) — excellent resistance to oils, fuels, and hydraulic fluids; colour: Black
- VMQ (Silicone) — wide temperature range, food-grade-compatible; colour: Red / White
- FKM (Fluorocarbon / Fluorine Rubber) — superior chemical and heat resistance; colour: Black / Brown
- Shape: Standard ring gasket / O-ring seal
- Meets standard O-ring dimensional specifications for easy drop-in replacement
- Suitable for static and dynamic sealing applications
Common Applications
- Hydraulic and pneumatic cylinders
- Pumps, valves, and pipe fittings
- Automotive engine components and fuel systems
- Industrial machinery maintenance
- Plumbing and water-treatment equipment
- Food-processing and laboratory equipment (VMQ grade)
Material Comparison at a Glance
| Material | Temp. Range | Best For | Colour |
|---|---|---|---|
| NBR | -40 °C to +120 °C | Oil, fuel, hydraulic fluid | Black |
| VMQ | -60 °C to +200 °C | High/low temp, food-safe | Red / White |
| FKM | -20 °C to +200 °C | Chemicals, fuels, solvents | Black / Brown |
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Frequently Asked Questions
Q: What is the difference between NBR, VMQ, and FKM O-rings, and how do I choose the right material?
A: NBR (Nitrile Rubber) O-rings are the most common general-purpose choice, offering strong resistance to petroleum oils, hydraulic fluids, and fuels at moderate temperatures. VMQ (Silicone) O-rings excel in extreme temperature ranges and are often used in food-processing or medical equipment. FKM (Fluorocarbon) O-rings provide outstanding resistance to aggressive chemicals, fuels, and high temperatures, making them ideal for demanding industrial environments. Choose based on the fluids, chemicals, and temperature range your application involves.
Q: What does CS 3.5 mm and OD 51–200 mm mean for O-ring sizing?
A: CS (Cross-Section) refers to the diameter of the O-ring's circular cross-section — in this case 3.5 mm. OD (Outer Diameter) is the overall outside diameter of the ring, available here from 51 mm up to 200 mm. To find the correct size for your fitting, measure the groove or housing inner diameter and confirm the required cross-section thickness. Matching both dimensions ensures a proper compression fit and reliable seal.
Q: Are these O-rings suitable for high-pressure applications?
A: Yes. Standard-dimension NBR, VMQ, and FKM O-rings with a 3.5 mm cross-section are widely used in low-to-medium pressure hydraulic and pneumatic systems. For very high-pressure dynamic applications, ensure the groove dimensions, surface finish, and back-up ring requirements comply with your system's engineering specifications. When in doubt, consult your equipment manufacturer's sealing guidelines.
Q: Can I use VMQ (Silicone) O-rings in contact with food or drinking water?
A: VMQ silicone is widely regarded as a food-compatible material and is commonly used in food and beverage equipment. However, compliance with specific food-safety regulations (such as FDA 21 CFR or EU 10/2011) depends on the exact silicone compound formulation. Please verify the specific grade with the supplier if regulatory compliance is critical for your application.
Production & Packaging Notice
To maintain high stock availability and fast shipping times, our items are sourced from multiple verified manufacturing facilities. While the core quality, materials, and product specifications remain identical, you may notice slight variations in the packaging design, manufacturing origin, or the wording of the printed instructions.
Materials + Care
We prioritize quality in selecting the materials for our items, choosing premium fabrics and finishings that ensure durability, comfort, and timeless appeal.
Shipping + Returns
We strive to process and ship all orders in a timely manner, working diligently to ensure that your items are on their way to you as soon as possible.