Thank you for viewing. This is a Sea & Sea port base, model S. No. 30108 I used this for over 10 years with an RDX-500D for macro photography. I think it's in relatively good condition, but please check the photos. This port base has no problems, but the RDX-500D body itself has reached the end of its life, so I'm selling it. I've used this for a long time, so I appreciate your understanding. #UnderwaterCamera #Housing #sea&sea