A heat recoverable article is so configured that it can be positioned around a pipe or cable joint or splice which it is desired to encapsulate or seal. Means for sealing a splice involving a plurality of cables of the same or varying sizes are provided. The article includes a closure means for holding the article together after it has been positioned around the splice to be sealed. In a preferred embodiment, the inner surface of the article contains a heat activated adhesive or sealant to environmentally encapsulate the splice and the outer layer of the article is a heat recoverable insulating material. In a particularly preferred embodiment, the article has self-contained heating means, which heating means comprises a polymeric material having dispersed therein a conductive filler, said heating means exhibiting a positive temperature coefficient of resistance so as to render it self-regulating.