My boyfriend works outside in all kinds of weather and he LOVES this shirt jacket.  He even made me buy him another one in a different color!  they completely replaced his carhartt heavy jacket he just wears one of these with a thermal shirt under it and he has better ease of movement.  They do run BIG...and they do not shrink very much I don't care what anyone says lol so if your man (or if you are a man that is) is a size Large....buy a Large.  Don't think that it should be bigger because it is a "jacket"!