Tubular sleeves formed from elongated flat sheets, particularly braided sheets are disclosed. Sheet material comprised of interlaced monofilaments is cold worked by the process of drawing the interlaced monofilaments over a forming edge with sufficient force and in a direction causing permanent elongation of the molecules of material on one side of the interlaced monofilaments. The cold worked monofilaments impart a permanent bias to the sheet causing it to curl about its longitudinal axis. Sleeves so formed may be slipped over or wrapped around bundles of wires or other elongated substrates, particularly those which include terminals, plugs and connectors of irregular dimension.