Replacement Focus Tab for the Leica 35mm 6 element Summicron v2/3. This is the same tab as the Summilux pre-asph, it fits both lenses, also fits the 40C.
Replaces the original plastic tab with a metal one. The convex tab is a bit deeper than the plastic one. Affixes to the lens with an M1.6 nut (not supplied) glued into the back of the focus tab. An M1.6x3mm screw then screws into the tab from inside the lens (the head of the screw may need to be filed down to fit).
See these threads here for details;
RFF;
LUF
Raw Silver option to get closer to matching the Titanium version of the lens.
Images curtosy of Shapeways user joshgoleman
To fit lenses with diameter equal to 49.8 mm