A zip fastener comprises two opposing and mutually engageable rows of zip teeth each being mounted upon a respective stringer tape; first and second sliders movably mounted upon the teeth, each slider being movable forward along the teeth to cause interdigitation of the teeth thereby to fasten the zip and backwards to cause extradigitation and unfastening of the zip, the sliders being mounted on the teeth in opposing directions such that motion of the sliders towards and away from each other results in the same action (e.g. fastening or unfastening) on the zip teeth; a docking member, mounted upon the teeth and being movable along the teeth, the docking member being mounted between the two sliders; and each slider being engageable with the docking member thereby to fasten the zip.