AS568-143 WN70 FDA White (NBR) Buna-N 70 Duro O-Ring

Dimensions: 2-7/16" ID x 2-5/8" OD x 3/32" CS

The AS568-143 is a Buna-N (Nitrile) 70A durometer O-Ring with an inside diameter of 2.425 inches and a cross-section of 0.103 inches. It is built for everyday sealing in oil, fuel and hydraulic systems. This O-Ring is stocked and shipped same-day by The O-Ring Store LLC, an ISO 9001:2015 certified distributor.

Stop leaks in oil, fuel and hydraulic systems with the AS568-143 Buna-N (Nitrile) O-Ring. This 70A durometer seal resists petroleum oils, fuels and hydraulic fluids from -40F to +225F. That makes it a solid pick for the jobs below, and a reliable replacement when a lesser O-Ring swells, cracks or takes a set.

Operating Temperature: -40 to +225F (-40 to +107C)

Material and Performance Details

Buna-N, also known as Nitrile or NBR, is the workhorse of the O-Ring world. It gives strong resistance to petroleum oils, fuels and hydraulic fluids at a fair price, which is why it fits so many everyday sealing jobs. It has good abrasion resistance and holds its shape under squeeze. The 70A durometer gives good squeeze and a firm seal without going brittle.

• Excellent resistance to: petroleum oils, hydraulic fluids, water, silicone greases, ethylene glycol, gasoline, diesel, LP gases and mineral oils
• Limited capability with: Skydrol, high ozone, sunlight and dilute acids
• Not compatible with: ketones such as MEK and acetone, esters, chlorinated hydrocarbons, strong acids, ozone and glycol brake fluid

Sizes and Measurements

• Dimensions: 2-7/16" ID x 2-5/8" OD x 3/32" CS
• Actual: 2.425" ID x 2.631" OD x 0.103" CS
• Metric: 61.6mm ID x 66.83mm OD x 2.62mm CS
• Part Number: WN70143
• AS568 Dash Number: -143
• Cross-references: Parker 2-143 (2.62mm CS / 0.103" CS)

Applications and Use Cases

White Buna-N is the food-grade version of nitrile, built with FDA-listed ingredients for parts that contact food, drink or skin. It is used in the food and cosmetic industry: food and beverage processing, dairy equipment, bottling and filling lines, and cosmetic manufacturing, where you need the oil and grease resistance of nitrile in a clean, food-safe compound. It keeps the same petroleum oil and fuel resistance as standard black Buna-N, so it still seals pumps, valves and fittings on the equipment side. Confirm the FDA grade for your application and we can send documentation on request.

• Food and beverage processing equipment
• Dairy and bottling lines
• Cosmetic manufacturing
• Filling and packaging machinery
• Drink and beverage dispensing systems
• Sanitary pumps and valves
• Food-contact fittings and connections

Key Specifications

• Material: Buna-N (Nitrile)
• Durometer: 70A Shore A
• Color: White
• Temperature Range: -40 to +225F (-40 to +107C)

Why Buy from The O-Ring Store LLC

The O-Ring Store LLC is an ISO 9001:2015 certified distributor with USA stock for fast delivery. Most in-stock items ship the same day. We handle custom sizes, and we can send full lot traceability and documentation when you need it. Every order gets checked through our Olypsys® scan-based quality system before it leaves the building. Fair pricing, real people and no runaround. We make getting O-Rings easy!

Frequently Asked Questions

Q: What are the exact dimensions of the AS568-143 O-Ring?
A: The AS568-143 O-Ring has an actual inside diameter of 2.425 inches (61.6mm), a cross-section of 0.103 inches (2.62mm) and an outside diameter of 2.631 inches (66.83mm).

Q: Is Buna-N compatible with oil and fuel?
A: Yes. Nitrile resists petroleum oils, hydraulic fluids, gasoline and diesel, which is why it is the standard pick for most oil and fuel sealing.

Q: What is the Parker equivalent of the AS568-143 O-Ring?
A: The Parker cross-reference for the AS568-143 is the Parker 2-143. Both share the same 0.103-inch (2.62mm) cross-section and 2.425-inch (61.6mm) inside diameter per the AS568 standard.