I already had these undershirts and it was time to get new ones. But I love them so much I wanted to make sure I got the exact same ones. I was able to make out the model number on my old one and found that these were the same model number. So I got them at the same size I was already using. They are nice and thin which I need as I live in the heat and don't need a lot of thickness under my dress shirt arm pit area. But when I got them I was shocked at how much bigger they were compared to my old ones. Luckily I washed them 2 times in hot water, cold rinse and they shrank down to the size of my previous ones.

I wear a Medium and I would say that unwashed before they shrink, they are more like a large. But were more of a true Medium after washing and matched my previous Medium undershirts. What a relief. I am glad I washed them instead of returning them as the "wrong size".