The next part of the construction is to stitch on the welt – a thin strip of leather running round the front of the shoe from heel to heel. The stitching secures the welt, outer leather and lining to the insole’s holdfast which essentially completes the permanent construction of the uppers. The sole is then bonded to the upper and stitched to the welt. If the sole needs to be replaced, a new sole will have to be bonded and stitched to the welt.