You can use Ollux hood with 43mm filter for new Leica Steel Rim lens.
This is specially designed by Korean technician.
Works with old Leica original filter. It may not work with B+W filters depending on thread pitch.
I am selling step down ring only OR step down ring with third party filter working with this ring.
Step down ring only is HKD 500.
Step down ring and third party filter: 700