Window 7 users: Hit "log In" to see if your computer is secure and can view the HTTPS:// secure connection, SSL. If not, please call in your O-Ring order. 

8am-4pm Pacific Mon-Fri | 208-413-6377


-444 FS70 Fluorosilicone (FVMQ) 70 Duro O-Ring


Quantity Discount Prices
Min:  2
  • Model: FS70444
  • 0 in Stock
  • 7-3/4"ID X 8-1/4"OD X 1/4"CS
  • Actual: 7.725"ID X 0.275"CS
  • Metric: 196.22mm ID X 6.99mm CS
  • PDF Data Sheets

O-ring Size: 7 3/4"ID X 8 1/4"OD X 1/4"CS

Blue Fluorosilicone O-rings 70 Durometer: AMS-R-25988 Cl1 Gr 70 (M25988/1)

Fluorosilicone rubber is an inorganic "hybrid" elastomer which combines the wide temperature range spectrum of silicone with some of the chemical resistance of fluorocarbon rubber. Primary use is in fuel delivery systems. Fluorosilicone rubber offers the best low temperature properties of any oil resistant rubber. Like all compounds based on silicone rubber, fluorosilicones have relatively low tear strength, abrasion resistance, and tensile strength, and therefore, are generally not suited to dynamic applications.

Chemical Resistance:

  • Aromatic mineral oils (IRM 903 oil)
  • Fuels
  • Low molecular weight aromatic hydrocarbons (benzene, toluene).

General Information:

  • Use where excellent fluid resistance is needed at extreme low temperature
  • Typically used in aircraft fuel & hydraulic systems
  • Excellent low temperature flexibility
  • Excellent heat resistance
  • Good compression set properties


  • Fuel injectors
  • Quick connects
  • Fuel pumps
  • Fuel tank seals
  • Any seal application dealing with fuels at low temperatures

Compound Material:

  • Blue in Color
  • 100% Virgin Materials
  • Meets Aerospace specification AMS R 25988 Class 1 Grade 70

Operating temperature: -76° to +392F° ( -60° to +200C°)

Be the first to write a review.  Write a Review.

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