DESCRIPTION
O-rings are the most common and cost-effective sealing elements available.  They seal over a wide range of pressure, temperature and tolerance.  They are an excellent option where space limitations are a concern.  And with proper hardware design, o-rings can seal a wide range of pressures from low vacuum up to several thousand PSI.  O-rings are available in a wide range of elastomers as well as PTFE. 
Silicone Rubber (Q, MQ, VMQ, PVMQ):  Silicones have good ozone and weather resistance as well as good insulating and physiologically neutral properties.  Many grades of silicone are food-grade and FDA-compliant, so they are widely used in the food, cosmetic, medical and pharmaceutical industries.  However, silicone elastomers as a group have relatively low tensile strength, poor tear strength and little wear resistance. 
Silicone o-rings are readily available in 70 and are typically rust red in color.  Many other specialty silicone compounds are available. 
 
SEAL INFORMATION
Low Temperature Range (F): DOWN TO -54F (SPECIAL COMPOUNDS DOWN TO -175F)  
High Temperature Range (F): UP TO 400F (SPECIAL COMPOUNDS UP TO 500F)  
Chemical Resistance:
-  ANIMAL AND VEGETABLE OIL AND GREASE.
-  HIGH MOLECULAR WEIGHT CHLORINATED AROMATIC HYDROCARBONS (INCLUDING FLAME-RESISTANT INSULATORS, AND COOLANT FOR TRANSFORMERS).
-  MODERATE WATER RESISTANCE.
-  DILUTED SALT SOLUTIONS.
-  OZONE, AGING AND WEATHER.
Not compatible with:
-  SUPERHEATED WATER AND STEAM OVER 250F.
-  ACIDS AND ALKALIS.
-  LOW MOLECULAR WEIGHT CHLORINATED HYDROCARBONS (TRICHLOROETHYLENE).
Durometer (Shore A): 70  
Max Pressure (psi): 1,450 DEPENDING ON APPLICATION  
Max Pressure (psi) WITH BACKUP RINGS: 5,000 DEPENDING ON APPLICATION  
Max Speed (ft/sec): 1.5  
Mating Surface Roughness - Ra (µin) - DYNAMIC: 16 MAX  
Mating Surface Roughness - Ra (µin) - STATIC: 32 MAX  
Part Number Definition (Inch): (AS568 3-DIGIT NUMBER)SI70  
Additional Part Number Definition (Inch): 4"ID X .210"CS   =   345SI70