Our standard lip material is NBR70 nitrile rubber. This is the default elastomer if no other materials are labeled.

     = NBR is a durable, general purpose material
-V = Viton or floro-elastomer can be used in high heat applications and is more durable than NBR.
-S = Silicone is well suited for very low to very high temperature applications or for low friction applications.
-P = Polyacrylate can be used with extreme pressure lubricants at a higher temperature than NBR.

Examples:
SE825-950-57SB is made with NBR70 nitrile rubber.
SE225-300-37SB-V is made with viton.

Please see the table below for the physical properties of these lip materials.

Resistance or Physical Property Nitrite Silicone Viton Polyacrylate
ASTM Designation 0141B NBR SI FPM ACM
Enduro Code -S -V -P
Specific Gravity 1.00 0.95 1.40-1.95 1.00-1.20
Durometer Range, Shore A 20-90 30-80 60-90 50-80
Resilience Good Poor Fair Fair
Tensile Strength (reinforced) psi 3500 900 2000 1500
Elongation (reinforced) % 350 200 200 200
Hysteresis Good Excellent Good Good
Compression Set Good Excellent Good Excellent
Electrical resistance Poor Excelent Good Fair
Gas Impermeability Good Poor Excellent Fair
Impact Fair Fair Good Good
Abrasion Excellent Fair Good Fair
Tear Good Fair Fair Fair
Cut Growth Good Fair Fair Fair
Flame Resistance Fair Good Excellent Poor
Stiffening °C +30 to -20 -60 to -160 +20 to -30 +14to-22
Brittle Point °C -65 -90 to -180 +10 to -60 0 to -44
Weather Good Excellent Excellent Good
Oxidation Fair Excellent Excellent Good
Ozone Poor Excellent Excellent Excellent
Radiation Fair Excellent Good Fair
Water Excellent Good Good Fair
Acid Good Fair Good Fair
Alkali Fair Fair Fair Poor
Aliphatic Hydrocarbons (gasoline, kerosene, etc.) Excellent Good Excellent Excellent
Aromatic Hydrocarbons (benzene, toluene, etc.) Good Poor Excellent Fair
Halogenated Hydrocarbons (Fluorine, clorine, etc.) Poor Fair Good Poor
Alcohols Excellent Excellent Excellent Fair
Synthetic Lubricants (diester) Fair Fair Good Fair
Silicates Good Poor Good Good
Phospates Poor Good Poor Poor