This part of IEC 60684 gives the requirements for two types of heat-shrinkable, polyolefin sleeving for bus-bar insulation, with a nominal shrink ratio of 2,5:1. This sleeving has been found suitable up to temperatures of 100 °C. Type A : Medium wall Internal diameter up to 170,0 mm typically Type B : Thick wall Internal diameter up to 165,0 mm typically These sleevings are normally supplied in colour, red or brown. Since these types of sleevings cover a significantly large range of sizes and wall thicknesses, Tables A.1 and A.2 provide guidance to the range of sizes available. The actual size and wall thickness shall be agreed between the user and supplier depending on the electric strength of the installed tubing offered and the requirements of the user. 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.