This is a good jacket - Mammut Wenaha Hardshell Jacket - Men's

This is a good jacket, however... despite following the explanation for proper sizing, I ended up ordering a Medium which turns out to be slightly too small for the person I had intended on giving it to. In fact, it is fair to say that the fit was too exact -- something you could, for example, put on an mannequin for a showcase, but not on a real person who needs to bend and flex their arms and body. I will keep the jacket and give it to someone else but I still felt it important to let other potential buyers know that the sizing of these jackets is not accurate. For a real person, consider purchasing one size larger.