Abstract: Rubber sleeve device for surrounding an electrical current conductor member. The device is adapted for axial displacement relative to the member as well as being prevented from turning relative to that member. The device has a first fastening portion in the form of a support ring composed of a heat-durable, shape-stable, insulating material embedded in the body of the sleeve. The ring is adapted to be in a fixed turning engagement and free fit relation with a fastening portion of the member whereby mutual axial movement of the sleeve and member is permitted. A second fastening portion axially bounds the first fastening portion and is adapted to engage directly and frictionally another fastening portion of the member whereby unintentional mutual axial displacement of the sleeve and the member can be prevented.