A slider for a zip fastener includes a lower part, an upper part and a puller. The lower part and upper part are interconnected by a hinge, whereby the slider can be set in an open and a closed condition, respectively. The puller, which is made of a resilient material and constitutes the part that the user holds when using the slider, includes locking pins for locking the lower part and upper part in the closed condition, and also dividing shoulders. The lower part includes a hole which can receive the locking pins of the puller in order to lock the lower part and the upper part in the closed condition. The upper part includes a cradle for the locking pins of the puller and also a slanted dividing body, which is capable of separating the dividing shoulders and therewith the locking pins of the puller. Further, the upper part includes two hinge taps and the lower part includes an area for cooperation with the hinge taps.