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-343 Teflon (PTFE) White 55 Duro Shore D O-Rings


Quantity Discount Prices

  • Model: TEF343
  • 1 in Stock
  • 3-3/4"ID X 4-1/8"OD X 3/16"CS
  • Actual: 3.725"ID X 0.210"CS
  • Metric: 94.62mm ID X 5.33mm CS
  • PDF Data Sheets

3-3/4"ID X 4-1/8"OD X 3/16"CS

Polytetrafluoroethylene (PTFE) O-rings

Teflon (PTFE) is a popular O-Ring material which is White in color. The Teflon O-Rings are popular for use in applications which require a chemically resistant and non-compressible material. PTFE is the chemically inert of the O-ring materials. It is resistant to most chemicals including acids, bases, oils, steam and other chemicals. It is also very tough and abrasive resistant. However the material is not easily compressed, and therefore may not seal as easily as some of the other polymers. Its outstanding tear resistnace and abrasive resistance result in its slippery surface properties that make it advantageous for use in seals in moving systems such as mass spectrometer probes and valves.


  • High heat resistance
  • High resistance to chemical agents and solvents
  • High anti?adhesiveness
  • High dielectric properties
  • Low friction coefficient
  • Non-toxicity

PTFE O-Rings are recommended for:

  • Chemical environments
  • Use is acidic or basic environments
  • Sealing of moving or sliding surfaces

PTFE is not recommended for:

  • Low compression vacuum sealing flanges
  • High vacuum seals
  • High temperature steam.


PTFE is one of the most thermally stable plastic materials. There is no appreciable decomposition at 260°C (500°F), so
that PTFE, at this temperature, still possesses the greater part of its properties. Appreciable decomposition begins at
over 400°C (932°F). The coefficient of the thermal conductivity of PTFE does not vary with the temperature. It is relatively high, so that PTFE can be considered to be a good insulating material. The mixing of suitable fillers improves the thermal conductivity.

Operating temperature:  -100°F to +500°F (-73.3°C to +260°C)

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Stock O-Rings in over 20 different compounds and durometers the following six are the standard rubber materials in a range of durometers (Shore A) hardness to satisfy practically any service condition:

Viton® O-Rings / FKM: Fluorocarbon (Viton®) exhibits exceptional resistance to chemicals, oils, temperature extremes (-13°F to +446°F), low compression set, low gas permeability and excellent aging characteristics. Applications include: aircraft engines, automotive fuel handling systems, and chemical processing industries. FKM is also suitable for high vacuum applications. It is not recommended for exposure to ketones, alkalis, and Skydrol® fluids. Custom compounds are available with improved chemical and low temperature resistance.
AS-568 Viton® O-Rings | Metric Viton® O-Rings

Buna-N O-Rings / Nitrile O-Rings / NBR: Nitrile (Buna-N) is the most widely used elastomer due to its excellent resistance to petroleum products, operating temperature range (-40°F to +257°F) and one of the best performance-to-cost values. It's an ideal material for aerospace, automotive, propane and natural gas applications. Special Hydrogenated Nitrile (HNBR) compounds can improve resistance to direct ozone, sunlight, and weather exposure while increasing temperature range to +300°F.
AS-568 Buna-N O-Rings | Metric Buna-N O-Rings

Ethylene-Propylene / EPDM O-Rings: EPDM has outstanding resistance to heat, water and steam, alkali, mild acidic and oxygenated solvents, ozone, and sunlight (-40ºF to +275ºF); but it is not recommended for gasoline, petroleum oil and grease, and hydrocarbon environments. This popular rubber compound is usually the first choice for low torque drive belt applications.
AS-568 EPDM O-Rings | Metric EPDM O-Rings

Fluorosilicone O-Rings / FVMQ: Fluorosilicone (-75º to +400ºF) combines the good high and low temperature stability of silicones with the fuel, oil, and solvent resistance of fluorocarbons. FVMQ is unparalleled for aerospace fuel systems, auto fuel emission control systems and to meet or exceed government, military, aerospace, automotive, industrial and commercial specifications. However, due to relatively low tear strength, high friction and limited abrasion resistance of these materials, they are generally not used in dynamic applications. They are also not recommended for exposure to brake fluids, hydrazine, or ketones.
AS-568 Fluorosilicone O-Rings | Metric Fluorosilicone O-Rings

Silicone O-Rings / VMQ: In the Silicone family, you will find compounds which are superior as static seals in extreme temperature conditions. Standard compounds handle operating temperatures -85º to +400ºF. Silicone compounds are popular in food and medical applications because they are very clean and do not impart odor or taste. Special Phenyl silicones can be used down to -148°F.
AS-568 Silicone O-Rings | Metric Silicone O-Rings

Neoprene® O-Rings / CR: Neoprene (-40º to +250ºF) is reasonably priced and features good resistance to petroleum oils, ozone, sunlight and oxygen aging, relatively low compression set, good resilience and outstanding physical toughness. It is the preferred sealing material for the refrigeration industry because of its resistance to ammonia and Freon®.
AS-568 Neoprene® O-Rings