The disclosure is related to the sealing of an opening in a body, e.g. a blood vessel or a human heart. In particular the disclosure relates to a collapsible medical closing device, a method and a medical system for delivering an object. Furthermore, the disclosure provides positioning of an object and sealing a gap of an opening in a body with one single piece of equipment. In one embodiment, a collapsible medical closing device (1) for closing a body opening, which comprises: a network of at least one thread (6), wire or fiber, and a closeable through channel in said network having an opening (12) for receiving an elongated unit herein for delivery of said collapsible medical closing device (1) over said elongated unit, wherein said elongated unit is a sheath, is provided.
