OK, here's the bottom line on this new overshirt joint: it's sick, there's nothing like it, and you should strongly consider adding it to your rotation.
This style, from Wax London's continuing overshirt collection, comes in a 6-wale wide cord (the 6 comes from the number of cords per inch!), making it rather unique.
It features two patch pockets and Corozo Nut buttons. It's best worn as a relaxed-fit shirt-jacket with a T-Shirt!
There you go. You're welcome. It's your new look for Spring. Thank me later. --Justin