The OSK™ O-Ring Service Kit K436X36H70 puts 436 HNBR 70 durometer O-Rings in 36 of the most-used SAE AS568 sizes on your shelf, so a repair keeps moving instead of stopping for one seal. HNBR (Highly Saturated Nitrile) handles petroleum oil, fuel, hydraulic fluid, sour gas, and R-134a automotive refrigerant, and it holds up from -40F to +300F (-40C to +149C). That makes this kit the right pick for automotive A/C work, oil field service, hydraulic repair, and any shop where standard Buna-N runs out of heat or ozone resistance. It covers the small and mid-range dash numbers from -005 through -219 that show up in fittings, pumps, cylinders, and A/C connections every day. If your work needs more than Buna-N but does not need the price of Viton, this is the kit.
Benefits
You are not just buying rubber. You are buying finished repairs. With 36 common AS568 sizes sorted and ready, a tech pulls the right O-Ring, drops it in, and closes the job instead of driving to the parts counter or waiting on a shipment. Service trucks carry this OSK™ kit so a field repair does not turn into a return trip. Maintenance teams keep it on the shelf so a machine does not sit down over one seal.
The HNBR compound is the other half of the value. It gives you the oil and fuel resistance of Buna-N with better heat, ozone, and wear resistance. In many jobs it can stand in for a more expensive fluorocarbon O-Ring. One kit, 436 pieces, and a very low cost per size.
Correct Size Coverage
Does this kit have your size? Here is the full list. All sizes are SAE AS568 dash numbers with 70 durometer HNBR O-Rings. Dimensions are ID x OD x CS in inches.
1/16" cross-section:
- 25pc -005: 3/32" ID x 7/32" OD x 1/16" CS
- 25pc -006: 1/8" ID x 1/4" OD x 1/16" CS
- 25pc -007: 5/32" ID x 9/32" OD x 1/16" CS
- 25pc -008: 3/16" ID x 5/16" OD x 1/16" CS
- 25pc -009: 7/32" ID x 11/32" OD x 1/16" CS
- 25pc -010: 1/4" ID x 3/8" OD x 1/16" CS
- 25pc -011: 5/16" ID x 7/16" OD x 1/16" CS
- 15pc -012: 3/8" ID x 1/2" OD x 1/16" CS
- 10pc -013: 7/16" ID x 9/16" OD x 1/16" CS
- 10pc -014: 1/2" ID x 5/8" OD x 1/16" CS
- 10pc -015: 9/16" ID x 11/16" OD x 1/16" CS
- 10pc -016: 5/8" ID x 3/4" OD x 1/16" CS
- 10pc -017: 11/16" ID x 13/16" OD x 1/16" CS
- 10pc -018: 3/4" ID x 7/8" OD x 1/16" CS
3/32" cross-section:
- 15pc -110: 3/8" ID x 9/16" OD x 3/32" CS
- 10pc -111: 7/16" ID x 5/8" OD x 3/32" CS
- 10pc -112: 1/2" ID x 11/16" OD x 3/32" CS
- 10pc -113: 9/16" ID x 3/4" OD x 3/32" CS
- 10pc -114: 5/8" ID x 13/16" OD x 3/32" CS
- 10pc -115: 11/16" ID x 7/8" OD x 3/32" CS
- 10pc -116: 3/4" ID x 15/16" OD x 3/32" CS
- 7pc -117: 13/16" ID x 1" OD x 3/32" CS
- 7pc -118: 7/8" ID x 1-1/16" OD x 3/32" CS
- 7pc -119: 15/16" ID x 1-1/8" OD x 3/32" CS
- 7pc -120: 1" ID x 1-3/16" OD x 3/32" CS
- 7pc -121: 1-1/16" ID x 1-1/4" OD x 3/32" CS
1/8" cross-section:
- 10pc -210: 3/4" ID x 1" OD x 1/8" CS
- 10pc -211: 13/16" ID x 1-1/16" OD x 1/8" CS
- 10pc -212: 7/8" ID x 1-1/8" OD x 1/8" CS
- 7pc -213: 15/16" ID x 1-3/16" OD x 1/8" CS
- 7pc -214: 1" ID x 1-1/4" OD x 1/8" CS
- 7pc -215: 1-1/16" ID x 1-5/16" OD x 1/8" CS
- 7pc -216: 1-1/8" ID x 1-3/8" OD x 1/8" CS
- 7pc -217: 1-3/16" ID x 1-7/16" OD x 1/8" CS
- 7pc -218: 1-1/4" ID x 1-1/2" OD x 1/8" CS
- 7pc -219: 1-5/16" ID x 1-9/16" OD x 1/8" CS
SAE AS568 Standard Kit
This is an SAE AS568 inch-standard kit. Every O-Ring in it matches an AS568 dash number, the sizing standard used across American-built equipment, fittings, pumps, and cylinders. It is not a metric kit, not a Boss or straight thread kit, and not a face seal kit. If you are working on European or Japanese equipment sized in millimeters, look at an OSK™ metric kit instead. If you need -900 series fitting O-Rings, you need a Boss kit in 90 durometer.
Material Compatibility
Every O-Ring in this kit is HNBR, also called Highly Saturated Nitrile or HSN. Think of it as Buna-N's tougher brother. Hydrogenating the nitrile polymer makes it far more resistant to heat, ozone, and oxygen while keeping the oil and fuel resistance Buna-N is known for. This compound is peroxide cured and green in color, which also makes an HNBR O-Ring easy to tell apart from a black Buna-N ring in the drawer. It meets ASTM D2000 M4DH716 A26 B36 EO16 EO36 F17 Z1 Z2.
HNBR has excellent resistance to:
- Petroleum oils and hydraulic fluids
- Gasoline and fuels
- Automotive refrigerants (R-134a)
- Hydrogen sulfide (H2S) and sour gas
- Carbon dioxide (CO2)
- LP gases
- Silicone greases and oils
- Di-ester base lubricants (MIL-L-7808)
- Ethylene glycol base fluids
HNBR is not recommended for:
- Halogenated hydrocarbons (carbon tetrachloride, trichloroethylene)
- Nitro hydrocarbons (nitrobenzene, aniline)
- Phosphate ester hydraulic fluids (Skydrol, Fyrquel, Pydraul)
- Ketones (MEK, acetone)
- Strong acids
- Automotive brake fluid
- Prolonged sunlight, UV, and weather exposure
Operating temperature runs -40F to +300F (-40C to +149C) for extended service. For any critical application, confirm the compound against your exact fluid, temperature, and pressure before you install it.
Durometer and Seal Performance
These are 70 durometer O-Rings, the standard general-purpose hardness. A 70 duro seal is firm enough to hold pressure in most fittings, pumps, and cylinders, but soft enough to conform to the gland and seal against normal surface finishes. Harder 90 duro O-Rings are used where extrusion resistance matters, like SAE straight thread and Boss fittings under high hydraulic pressure. For general repair and maintenance work, 70 duro is the right hardness, and HNBR adds wear resistance that ranks among the best of any elastomer. That means longer seal life in moving and high-wear applications.
Best Uses
This OSK™ kit fits shops and service work where oil, fuel, heat, and refrigerant show up together:
- Automotive A/C repair (R-134a systems)
- Oil field and sour gas service
- Hydraulic repair shops
- Maintenance shops and manufacturing plants
- Service trucks and field repair
- Farm and heavy equipment repair
- Fuel system and small engine work
- General shop repair on petroleum-lubricated equipment
This kit is not the right pick for unknown chemicals, brake fluid systems, Skydrol hydraulics, or critical aerospace, medical, or highly specified work unless material, certification, and traceability are confirmed first.
Quality and Reliability
This is a professional repair kit, not a bargain-bin assortment. You get a known compound (HNBR 70 duro, peroxide cured, ASTM D2000 M4DH716 rated), correct AS568 sizes, and useful quantities of each. The O-Ring Store LLC operates an ISO 9001:2015 certified quality system and verifies compounds through the Olypsys® quality verification system, so the ring you pull out of the kit is the ring the label says it is. That matters. A wrong-size or wrong-material O-Ring means a repeat failure, and a repeat failure costs a lot more than the kit did.
Organized Storage Case
The kit keeps all 36 sizes sorted and ready to grab, so a tech finds the right O-Ring during the repair instead of digging through a coffee can of loose rings. It stores easily on a shop shelf or in a service truck.
Piece Count and Refill Value
The kit holds 436 O-Rings across 36 sizes, with 7 to 25 pieces per size. The quantities are weighted toward the smallest, most-used sizes, so the rings you burn through fastest are the ones you have the most of. And here is the part that saves real money: when a popular size runs low, you can reorder that exact HNBR O-Ring by the single size from The O-Ring Store. You refill the compartment. You never throw out a whole kit because three sizes went empty first.
Before You Buy
Match the O-Ring size to your gland or your original O-Ring by ID, OD, and cross-section. Match the material to your fluid, temperature, pressure, and environment. HNBR is excellent in oil, fuel, and refrigerant service, but it does not belong in brake fluid, ketones, or phosphate ester hydraulics. Not every rubber works in every fluid. For critical work, confirm material, hardness, certification, and traceability before you install.
Why Buy From The O-Ring Store LLC
The O-Ring Store LLC is an ISO 9001:2015 certified O-Ring and seal distributor, and we work with O-Rings every day. When you buy an OSK™ O-Ring Service Kit from us, you get clear sizing, straight answers about materials, single-size refills to keep the kit working for years, and same-day shipping on in-stock items. If you are not sure this is the right kit for your equipment, ask us. We would rather help you get the right seal the first time. We make getting O-Rings easy!
FAQ
What is the OSK™ K436X36H70 O-Ring kit used for? It is an industrial repair and maintenance kit with 436 HNBR 70 durometer O-Rings in 36 SAE AS568 sizes. Shops use it for automotive A/C repair, hydraulic repair, oil field service, and general equipment maintenance where oil, fuel, heat, or R-134a refrigerant is present.
Is this an SAE or metric O-Ring kit? SAE. Every O-Ring matches a standard AS568 dash number from -005 through -219, sized in inches. For millimeter-sized equipment, choose an OSK™ metric O-Ring kit instead.
What material are the O-Rings in this kit? HNBR (Highly Saturated Nitrile), 70 durometer, green, peroxide cured, rated ASTM D2000 M4DH716. HNBR handles petroleum oils, fuels, hydraulic fluid, sour gas, and R-134a refrigerant from -40F to +300F (-40C to +149C).
Does HNBR work with hydraulic oil? Yes. HNBR has excellent resistance to petroleum-based hydraulic fluids and oils. It is not compatible with phosphate ester hydraulic fluids like Skydrol, Fyrquel, or Pydraul.
Can I refill this kit when sizes run out? Yes. Every AS568 size in this kit can be reordered from The O-Ring Store by the individual size, so you restock the sizes you use most instead of replacing the whole kit.
What is the difference between HNBR and regular Buna-N? HNBR is a hydrogenated version of Buna-N nitrile. It keeps the same oil and fuel resistance but adds better heat resistance (+300F versus about +225F), better ozone and oxygen resistance, and some of the best wear resistance of any elastomer. In some jobs it can replace more costly Viton/FKM.
