Whether two-component or three-component syringes (with rubber plugs at the end of the piston), syringes for manual use or for use with syringe pumps (dispensing pumps for intravenous administration of medication), a decisive criterion is not only the constant tightness of the piston referred to above but also the elasticity of the seal which must ensure easy sliding of the syringe cylinder for exact dispensing without a slip-stick effect. It must be possible to adjust the dose and flow of the active ingredient using the sliding properties displayed by the seal material. Furthermore, sterility is a must in order to prevent leaks, malfunctions or signs of ageing. Syringes are usually sterilized in advance in an ETO (ethylene oxide) sterilization process to guarantee 100 percent sterility and therefore safety for patients and their environment.