Abrasion resistance is a general term that indicates the wear resistance of a compound. Where “tear resistance” essentially concerns cutting or otherwise rupturing the surface, “abrasion resistance” concerns scraping or rubbing of the surface. This is of major importance for dynamic seal materials. Only certain elastomers are recommended for dynamic O-ring service where moving parts actually contact the seal material. Harder compounds, up to 90 durometer, are normally more resistant to abrasion than softer compounds. Of course, as with all sealing compromises, abrasion resistance must be considered in conjunction with other physical and chemical requirements.