denoted by h the upper and respectively lower width of a loop is denoted by l1 and l2 respectively and the graduation of the meshwork 6 in the vertical direction with respect to the height h defined as the spacing of a center of a loop to the center of the next following identically aligned u shaped loop is called t the width of the loop in the region of the respective u base can vary for differently aligned u loops which in each case follow one another in the graduation direction with alternating alignment the knit jacket 6 is preferably applied to the bellows in such a way that the height h of the loops extends in the axial direction of movement i e in parallel to the axis of the bellows in a concrete example a bellows 1 was utilized in accordance with fig2 having 9 wave crests exhibiting differing outer diameters of between 65 and 70 mm the inner diameter of the wave troughs was uniformly about 50 mm the installation length was about 45 mm the bellows consisted of ferritic steel x 10 crnimoti 18 10 material number 1 4571 according to din german industrial standard 17007 namely two ply the thickness of each ply being 0 15 mm the.