Wetzlar made fine quality wide angle lens for the Leica M3 cameras.  Not to be confused with the regular f3.5 summaron the f2.8 version came out after the 8 element summicron and also uses the then new rare earth glass elements.  (In our experience the 2.8 summaron is even sharper than the 8 Element summicron from the same era.)  A little dust in the viewfinder but lens optics are perfect.   Note - ONLY for the M3 model.
 
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