I have broad shoulders and a belly.  Regular T shirts are either baggy or tight up top bit cut off right at the point where my pants hit my body.  Often the under shirt would come untucked under a dress shirt or collared shirt.

These T Shirts solve that problem.  They go over my belly and tuck in just as needed.

I'm 6 foot, 225lbs.  I had ordered the XL's and they went down to me knees.  The Largest fit me perfect.  My wife is going to keep the extra larges as bed wear.