Abstract: A product having a metal strip and a central longitudinal axis. The strip has two or more strip parts, each having a common radius of curvature defining a helix having an angle being offset from one another in the direction of the axis. A cross section of the strip parts causes them to be interlocked together throughout their lengths to define a flexible metal tube. The outside diameter of the tube is between ?? and 1?? and the helix angle of each strip part is between eight and thirty degrees.

Abstract: A product having a metal strip and a central longitudinal axis. The strip has two or more strip parts, each having a common radius of curvature defining a helix having an angle being offset from one another in the direction of the axis. A cross section of the strip parts causes them to be interlocked together throughout their lengths to define a flexible metal tube. The outside diameter of the tube is between ?? and 1?? and the helix angle of each strip part is between eight and thirty degrees.

Abstract: The product is of the type having a metal strip encircling a central longitudinal axis in a coiling manner, the strip defining a tubular arrangement, the tubular arrangement having a groove defined by the edges of the strip. The improvement in the product comprises: a yarn secured to the tubular arrangement, encircling the central longitudinal axis in a coiling manner and occupying the groove. The process is for use with a product, to product being of the type having a metal strip encircling a central longitudinal axis in a coiling manner, the strip defining a tubular arrangement, the tubular arrangement having a groove defined by the edges of the strip. The process comprises the steps of: coiling a yarn about the tubular arrangement such that the yarn encircles the central longitudinal axis in a coiling manner and occupies the groove, thereby to produce a marked product.