Nauticam Ext ring 20 w/ lockThe Nauticam Extension Ring 20 with Lock is part of the N120 Port System and can be used to add 20mm effective length to an N120 Port setup. This extension ring features a removable bayonet mount and is compatible with Nauticam Extension Ring 10 (SKU 21110). See Port Chart for more details on choosing the correct extension and port. Technical Specifications Depth Rating 150m Port System N120 Weight 0. 20kg Port Opening Diameter 98mm Port Diameter Body