Nauticam N50 short port w/ M67 threadThis short port is part of the N50 port system and features an optical glass front element and anodized aluminum construction. Different size ports are available to support a wide variety of lenses and housing types. Port extensions or adapters may be necessary for some ports and housings. The N50 Short Port offers precise placement of wide lenses very close to the port's front element at its widest angle zoom position. Zoom through is not available