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O-rings


Parco is a leading manufacturer of O-rings. An O-ring is a solid-rubber seal shaped like a doughnut or torus. When compressed between mating surfaces, an O-ring blocks the passage of liquids or gases. Parco O-rings are available in a wide range of standard and non-standard sizes that are suitable for nearly all sealing applications. Two dimensions describe the size of an O-ring: its inside diameter (ID) and its cross-sectional diameter (CS).

Standard Sizes

There are 369 standard sizes of O-rings with inside diameters ranging from 0.029 to 25.940 inches and cross sections ranging from 0.040 to 0.275 inch. Standard sizes are available in five popular cross-sectional diameters (0.070, 0.103, 0.139, 0.210 and 0.275 inch). Each O-ring size is identified by a "dash number." Each Parco "dash number" is the same as Aerospace Standard AS568B, Aerospace Size Standard for O-rings. Those designations are used throughout the O-ring industry. Parco offers O-rings in all 369 standard sizes and has hundreds of molds for non-standard sizes. In addition, Parco also offers all 20 sizes of boss seals used for sealing straight-thread tube fittings on a boss.

Metric Sizes

Standard metric sizes for O-rings are defined by International Standard ISO 3601-1:2002: Fluid power systems—O-rings—Part 1: Inside diameters, cross sections, tolerances and size identification code. Currently, ISO sizes do not use a dash numbering system like the Aerospace Standard. ISO cross-sectional diameters differ from the Aerospace Standard by less than 0.001 inch. Therefore, many AS568B sizes are interchangeable with an ISO size. Be sure to consult ISO 3601-1 for specific dimensions, as inside diameters may differ. If Parco does not have a mold for a non-standard size or a particular ISO size, we can make one for you.

 

View Parco’s O-ring Size Chart for additional information on O-ring sizes, dimensional tolerances, and cross-sections.

 
Below is a list of our Popular Compounds for O-rings. If you need additional help, use Parco’s Compound Wizard to search our compound library.

 

Compound

Elastomer

Color

Description

5601-70Ethylene-propyleneBlack70-durometer ethylene propylene; general purpose; sulfur-cured; FDA-conforming.
5778-70Ethylene-propyleneBlack70-durometer ethylene propylene; internally lubricated; peroxide-cured; NSF-61 listed.
5611-80Ethylene-propyleneBlack80-durometer ethylene propylene; peroxide-cured; MIL R 3065 compliant.
9005-75FluorocarbonBrown75-durometer fluorocarbon.
9505-75FluorocarbonBrown75-durometer fluorocarbon; low cost; general purpose.
9009-75FluorocarbonBlack75-durometer fluorocarbon; AMS 7276 and MIL R 83248 compliant; QPL-listed.
9266-75FluorocarbonBlack75-durometer fluorocarbon; AMS 7276 and MIL R 83248 compliant; QPL-listed.
9500-75FluorocarbonBlack75-durometer fluorocarbon; low cost; general purpose.
9009-90FluorocarbonBlack90-durometer fluorocarbon; AMS 7259 and MIL R 83248 compliant; QPL-listed.
9021-95FluorocarbonBlack95-durometer fluorocarbon.
1902-60FluorosiliconeBlack60-durometer fluorosilicone; AMS R 25988, AMS 3325, and MIL R 25988 compliant.
1933-70FluorosiliconeBlack70-durometer fluorosilicone; AMS R 25988 and MIL R 25988 compliant.
2269-70HNBRBlack70-durometer HNBR; peroxide-cured.
2269-90HNBRBlack90-durometer HNBR; peroxide-cured.
3110-70NeopreneBlack70-durometer neoprene; general purpose; AMS 3209 and MIL PRF 1149 compliant.
4457-65NitrileBlack65-durometer nitrile; AMS P 5315 compliant.
0228-70NitrileBlack70-durometer nitrile; FDA-conforming; UL-listed; SAE J120 R1 compliant.
4200-70NitrileBlack70-durometer nitrile; FDA-conforming; AMS 3215 compliant; UL-listed.
4900-70NitrileBlack70-durometer nitrile; low cost; general purpose.
4067-70NitrileBlack70-durometer nitrile; MIL P 25732 compliant; QPL-listed.
4456-70NitrileBlack70-durometer nitrile; MIL G 21569, MIL P 82745, and SAE J120 R1compliant
4367-70NitrileBlack70-durometer nitrile; peroxide-cured; AMS P 83461 and MIL P 83461 compliant; QPL-listed.
0483-80NitrileBlack80-durometer nitrile; sulfur-cured.
2067-90NitrileBlack90-durometer nitrile.
4900-90NitrileBlack90-durometer nitrile; low cost; general purpose.
4177-90NitrileBlack90-durometer nitrile; sulfur-cured.
4058-90NitrileBlack90-durometer nitrile; sulfur-cured; MIL R 3065 compliant.
1200-70SiliconeBrick Red70-durometer silicone; general purpose; AMS 3304 compliant.

 
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