Slide fastener

A slide fastener chain is provided which curves out of plane in its natural state, when first and second stringers (12a, 12b, fig.15) are interdigitated. The first and second stringers each comprising a tape having a row of coupling elements (68, 70, fig.8) mounted on a longitudinal edge thereof. The tape of each of the first and second stringers is generally planar when the coupling elements of the first stringer are not interdigitated with the coupling elements of the second stringer. The head (54b, fig.8a) and neck (56b, fig.8a) portions of the coupling elements of the first and second stringers are shaped such that, when coupling elements of the first stringer are interdigitated with coupling elements of the second stringer, the longitudinal edge of the second stringer in the region of said at least one of the coupling elements of the first stringer, and of first and second adjacent coupling elements forms a curve having a centre of curvature (CC) which lies beneath the plane of the tape of the second stringer.