This is a two layer shirt.  No binding under the arms and no seam iritation down the sides.  Holds everything firmly and keeps lower back warm and stable.

There are several keys things however.  Measure your chest and buy the size indicated.  Buying a smaller size will be uncomfortably tight with binding under the arms.  This is NOT an exercise shirt.  If you are very actively employed (physical labor, etc) this is probably not for you unless you really want to work up a sweat.  I wear this in the car, office and for light walking around in 70-80 degree weather.  90+ heat and physical activity is not what this shirt is for.  Also, if you have shoulder problems it may be difficult to pull over your head.

It does help my back and general appearance.  I plan to get a couple more.