These are great undershirts.  I have been buying these same shirts for years.  I find that they last about 6 months or so before they get a bit old and stretched out - stained, etc.  The sizing runs very accurate.  I wear a 42 jacket and the large fits fine with a bit of extra room.  The medium is too tight.  The shirts do not shrink in the wash and I really like the tagless design.