This part of IEC 60684 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. It is normally offered for sale with an internal diameter up to 25 mm in the following colours: black, white, red, yellow, blue and translucent. Sizes or colours other than those listed in this standard may be available as custom items. These items are considered to comply with this standard if they comply with the property requirements listed in Tables 2, 3, 4 and 5, excluding dimensions. Materials which conform to this specification meet established levels of performance. However, the selection of a material by a user for a specific application should be based on the actual requirements necessary for adequate performance in that application and not based on this specification alone.