CSN EN ISO 7197 This document specifies the performance requirements for sterile, single-use non-active hydrocephalus shunts. This includes not only the valve, but also additional components such as tubes and reservoirs. This document does not provide any recommendations on which type of valve is most suitable for any specific context of use. This document specifies the mechanical and technical requirements to manufacture shunts and the technical information of the valve to be supplied by the manufacturer. This document does not apply to active implants for the treatment of hydrocephalus. Original English text of CSN EN Standard. The price of the Standard included all amendments and correcturs.