A tubular elastic covering for electric components is provided to obtain predetermined values of mechanical and electric/environmental requirements. The mechanical requirements include expandibility and elastic recovery in a radial direction. The electric/environmental requirements include resistance to tracking and resistance to solar radiation. The covering includes an inner insulating layer and an outer insulating layer coaxial with each other, in superposed relationship and bonded together. The covering is made of blends of cross-linked polymeric material, in which the cross-linked blend forming the inner layer has predetermined values of the mechanical requirements and the cross-linked blend forming the outer layer has predetermined values of the electric/environmental requirements. This invention also describes a method of making this covering, a termination for electric cables utilizing this covering, and a method of mounting the termination to an electric cable.