a seal for use with a container having a flexible gusset sheet or the like including a pair of slide fastener runner tapes , releasably interengageable grippers on the tapes , a slider moveable along the tapes toward one end thereof for interengaging the grippers and in the opposite direction for releasing the grippers , a slider pull or tab carried by the slider , a cover configured to conformably cover the slider pull when the grippers are closed , the cover being mounted to the sheet for movement into and out of its covering relation to the slider pull , and registerable openings in the slider pull and cover for receiving therethrough a sealing shackle when the grippers are interengaged .