Howshot 67mm threaded mount base is suitable for 144mm(+/-1mm) (Sea&Sea RDX Standard Port #30107) flat ports. It will protect the ports securely without rotating. Or easily attach macro lens with 67mm threaded, like INON UCL-330, UCL-165M67, SubSee +5/+10 or etc. close-up lenses to have macro photos.
|Wet Lenses||M67 (67mm) Thread|