This underwear is not a "T-back",
and when I wore it,
the butt area was almost the same as a Rio back,
there was an "uncomfortable gap" in the area of fabric in the front,
but I was able to adjust that gap to the ideal width with my own sewing technique,
and as a result, it has the ideal "feel" to wear,
and it's the ideal underwear.
For those who enjoy looking at themselves in the mirror,
you'll be impressed by the different "attractiveness" and "comfort" of this shape compared to regular underwear,
and you'll be glad you bought it.