Few days ago I received the first prototype of the TAAB lens focus tab – it allows you to add a Leica M style focusing to pretty much any lens:
I currently do not own any M lenses without a focusing tab, but you can see how the rubber band looks on the 50mm Summilux lens:
The TAAB lens focus tab comes in three different sizes:
and can be used on other lenses as well:
Keep in mind that the above pictured TAAB is a prototype that is made using water jet manufacturing technologies and because of this, the finish will not be smooth or uniform. The final production units will be made using liquid injection molding which will ensure a quality finish and uniformity.