From the website:

I have always loved the way that collared shirts look under a contrasting short-sleeve or sleeveless layer. And sweater-vests are always cool in a kind of nerdy un-cool sort of way. Hence, this design (which is intended to look like a sweater-vest over a collared shirt) was born.

SIZE
S M, L, XL, XXLn size S)

FINISHED MEASUREMENTS
Chest: 34 38, 42, 47, 52 inches
Length: 25.5 26.5, 27.5, 28.5, 29.5 inches