OSK™ Industrial Boss Seal Kit | 212 Piece Hydraulic SAE | Buna-N 90

Get leak-free Boss connections, reduce downtime, and keep your hydraulic systems running with confidence.

The OSK™ Industrial Boss Seal Kit K212X20N90-OSK is designed for technicians and maintenance teams who want dependable sealing without delays. This kit delivers the most common SAE Boss O-Ring sizes in one organized solution, helping you fix leaks fast, avoid repeat failures, and keep equipment in service.

Built with Buna-N 90 durometer material, these O-Rings are optimized for high-pressure hydraulic Boss straight thread tube fittings. The higher durometer means better extrusion resistance, longer service life, and fewer callbacks for your customers.

At The O-Ring Store LLC, we focus on one thing: making your job easier while protecting your equipment and uptime.

Operating temperature: -40° to +250°F (–40° to +121°C)

Material & Performance Details

These O-Rings are manufactured from Buna-N (Nitrile) 90A, a proven compound for demanding hydraulic applications.

Material advantages

• High hardness for high-pressure Boss sealing
• Excellent oil and fuel resistance
• Strong abrasion resistance for long service life
• Reliable sealing in cold start conditions

Durometer: 90A
Color: Black
Cure: Sulfur-cured for high-pressure performance

Excellent resistance to:

• Petroleum-based hydraulic oils
• Hydrocarbon fuels
• Silicone oils and lubricants
• Di-ester lubricants
• Ethylene glycol based fluids
• Water and cold water systems

Limited capability with:

• Mild acids
• Mild alkalis

Not compatible with:

• Phosphate ester hydraulic fluids
• Ketones
• Halogenated hydrocarbons
• Ozone, UV, and weather exposure
• Strong acids

Sizes & Measurements

This kit includes 212 total O-Rings across 20 SAE Boss sizes, giving you outstanding coverage and value.

Included quantities and dash sizes

• 10 each: -901, -902, -903, -904, -911, -912, -913, -914, -916, -918, -920, -924, -928, -932
• 12 each: -905, -906, -907, -908, -909, -910

Material standard

• AS568 SAE Boss sizes
• Designed for SAE straight thread Boss fittings

Applications & Use Cases

This Boss Seal Kit is commonly used in:

• Hydraulic systems and power units
• Mobile and industrial equipment
• Pumps, valves, and manifolds
• Hydraulic cylinders
• SAE Boss straight thread tube fittings
• Pneumatic systems requiring higher durometer seals

Ideal for maintenance shops, OEM service departments, field technicians, and distributors supporting hydraulic equipment.

Key Specifications

• Material: Buna-N (Nitrile)
• Durometer: 90A
• Color: Black
• Cure system: Sulfur-cured
• Temperature range: -40° to +250°F (–40° to +121°C)
• Standards:
  • ASTM D2000-75 Grade 7BG915 B14 E14 E34 E51 E61 F16 L14
  • ASTM D2000-01 Grade M7BG910 B14 EA14 EF11 EF21 EO14 EO34 F16

Why Buy from The O-Ring Store LLC

When you buy from us, you get more than a seal kit.

• ISO9001:2015 certified quality systems
• USA-based inventory for fast delivery
• Same-day shipping on in-stock items
• Full lot traceability available on request
• Knowledgeable technical support from real people
• Consistent quality you can trust
• No filler sizes, only what technicians actually use

We are a small, focused distributor that cares about your success. Our goal is to help you beat downtime, reduce waste, and keep your customers satisfied.

Frequently Asked Questions

Q1: Why choose 90 durometer Buna-N for Boss fittings?
A 90A O-Ring provides higher extrusion resistance than softer compounds, making it ideal for high-pressure SAE Boss applications where reliability matters.

Q2: Are these O-Rings compatible with standard SAE Boss fittings?
Yes. All sizes in this kit are designed for SAE straight thread Boss fittings and meet AS568 dimensional standards.

Q3: Is this kit suitable for field service trucks?
Absolutely. This kit was built for service efficiency, giving technicians the most common Boss sizes in one compact, organized solution.