A device having an inner seal and a retaining assembly seals a puncture in a blood vessel. The inner seal is placed inside the blood vessel and seals the puncture by contacting the inner surface wall of the blood vessel. The retaining assembly has at least two loops which engage the inner seal. Each loop may remain in substantial contact with the inner seal for substantially 360 degrees of the travel of each loop. The at least two loops may lie in a plane which is parallel to both the major axis of the inner seal and a folding axis. A locking member may be slid along the retaining assembly so as to contact the outer surface wall of the blood vessel.