This quality tack strip comes in a stiff card of 12mm width or plastic of 10mm width, and offered in a range of lengths to suit your end use. Back tack, as it is widely referred to, is used at the top of backs and arms and also headboards or wherever else an invisible join is required. The tacking strip is laid over the underside of the fabric and tacked into place so that it forms a smooth, straight edge when the fabric is folded back over it, to create a straight concealed seam. Manufactured from stiff, hardened cardboard, or plastic. This is a simple product which really makes the difference between an average and professional finish.