IEC 60684-3-246:2007 defines requirements for dual wall, non-flame retarded, heat shrinkable, polyolefin sleeving. This sleeving has been found suitable for use up to 110 °C. The sleeving consists of an outer layer made of a semi-rigid cross-linked material. The inner layer is a substantially non-cross-linked polyolefin that flows and fuses during the shrinkage process to provide a seal. The major technical changes with regard to the second edition concern a better alignment with existing national specifications.