Best wide angle lens for the leica m9?

Here is what the site says about that.

From Leica M9: Leica M9: A rangefinder by Leica with a 18-megapixel full frame sensor, announced in 2009. The first full-frame digital M; check whether its CCD sensor has been replaced for corrosion. Specs - Maker: Leica - Mount: Leica M - Sensor: Full frame, 36 x 24mm, crop factor 1.0 - Resolution: 18 megapixels - Stabilisation: none in the body; use stabilised lenses for slow shutter speeds - Announced: 2009 - Type: rangefinder Focal ...

From Laowa 15mm f/4 Wide Angle Macro: Laowa 15mm f/4 Wide Angle Macro: A macro lens by Laowa for Full frame cameras, 15mm f/4. An ultra-wide that focuses to 1:1.

Quoted from this site's pages.