Markenware Nauticam Panasonic und Olympus – Macro port 45 for Leica DG Macro Elmarit 45mm F2.8 ASPH

In addition, you can add the M67FLIP Diopter holder.
If you mount a macro wetlens on that, you will be able to flip between -up and ultra macro in a heart beat, and you won’t loose your lens in the mounting process. Very handy under water!