The back/bottom of this vest has what I call a draft flap which have become fairly popular with my customers. The first request for it was a guy who wanted the back of his vest longer so his back wouldn't get drafty cold sitting in his pick-up during the long Winters. Since then, bikers have come to also like them as a bit of a wind break on the back. In fact, I've now come to make them with several different curves across the bottom.