A cable closure system comprising: a base defining at least one drop cable port, the base having a cable organizer attached thereto; a dome mountable to the base to cover the cable organizer, the dome being configured to sealingly engage the base when mounted to the base; a sealing and retention arrangement mountable to the base at the drop cable port, the sealing and retention arrangement including: a gel block configured to be disposed within the drop cable port, the gel block being configured to seal a plurality of drop cables within the drop cable port; a cable retention block for receipt at the drop cable port, the cable retention block having a plurality of open-ended, outwardly-facing slots, each of which is configured to retain one of the plurality of drop cables sealed by the gel block; a first mounting arrangement for mounting the cable retention block to the base; characterised in that the cable closure system further comprises: a second mounting arrangement for releasably mounting the gel block to the cable retention block, wherein releasing the gel block from the retention block and deactivating the gel block enables the gel block to be removed from the drop cable port while the retention block remains attached to the base by the first mounting arrangement. a base defining at least one drop cable port, the base having a cable organizer attached thereto; a dome mountable to the base to cover the cable organizer, the dome being configured to sealingly engage the base when mounted to the base; a sealing and retention arrangement mountable to the base at the drop cable port, the sealing and retention arrangement including: a gel block configured to be disposed within the drop cable port, the gel block being configured to seal a plurality of drop cables within the drop cable port; a cable retention block for receipt at the drop cable port, the cable retention block having a plurality of open-ended, outwardly-facing slots, each of which is configured to retain one of the plurality of drop cables sealed by the gel block; a first mounting arrangement for mounting the cable retention block to the base; characterised in that the cable closure system further comprises: a second mounting arrangement for releasably mounting the gel block to the cable retention block, wherein releasing the gel block from the retention block and deactivating the gel block enables the gel block to be removed from the drop cable port while the retention block remains attached to the base by the first mounting arrangement. a gel block configured to be disposed within the drop cable port, the gel block being configured to seal a plurality of drop cables within the drop cable port; a cable retention block for receipt at the drop cable port, the cable retention block having a plurality of open-ended, outwardly-facing slots, each of which is configured to retain one of the plurality of drop cables sealed by the gel block; a first mounting arrangement for mounting the cable retention block to the base; characterised in that the cable closure system further comprises: a second mounting arrangement for releasably mounting the gel block to the cable retention block, wherein releasing the gel block from the retention block and deactivating the gel block enables the gel block to be removed from the drop cable port while the retention block remains attached to the base by the first mounting arrangement.