Abstract: An improved shrinkable covering made of a shrinkable plastic compound having an inlay of non-recoverable threads and recoverable threads has the recoverable threads arranged with excess length, preferably in helical form, and extending in the stretching and shrinking direction of the covering. As a consequence of this excess length, the recoverable threads are not subjected to any additional stretching during the stretching process of the covering. The recoverable threads act as "swelling agents" in the shrinking process and seal off any longitudinal capillary cavities which may be produced during the production process of the shrinkable covering.

Abstract: A heat-shrinkable envelope of at least one shrinkable surface layer and a reinforcing insert has the reinforcing insert formed of a grid of plastic, and the grid is shrinkable in the shrink direction of the shrinkable layer.

Abstract: A composite envelope composed of a heat-shrinkable foil with a reinforcing layer containing tear-resistant fibers. The reinforcing layer is formed of a material which will melt below or at the temperature to which the heat-shrinkable foil is heated to stretch the foil and cause it to shrink back to its original condition so that the tear-resistant fibers are free to move in the melted material. Preferably, the composite is formed by providing carrier elements either having the fibers wrapped thereon or contained therein and assembling them with the shrinkable foil, heating to a stretching temperature to cause a melting of the carrier elements and stretching the foil at that temperature to create the memory and then holding the stretching forces until the foil has cooled to solidify the material of the carrier elements to form the reinforcing layer.