I love these undershirts!  First, the main reason is:  Two tiny tucks in the fabric at the bottom of the arm hole; they take out the excess fabric that causes EVERY other undershirt to "blouse," or fit baggy; I've tried virtually every other brand - Calvin, Ralph, Hanes, Fruit, blah, blah, blah...they ALL "bag" under the arm...but these don't.  Second, they are very light, which is a plus living in South Florida; yes, the lighter fabric may mean they don't last quite as long as other brands, but I'll take the comfort and tailored fit over longevity.  I used to find them in 3-packs for $9.99 at Marshall's or Nordstrom's Rack, but no more; now, I have to pay much more - even though discounted - but still believe them to be well worth the price.  Try them!