Men's Classic Winter Black Leather Car Coat - 3/4 Length

My regular size is M, however, this coat runs small, I had to return the item, and ordered size L, instead. Which fits much better, however, the sleeves seem to be a bit too long. I am 6'1" tall and rather slim. The coat arrived packed in two plastic bags, what caused wrinkles and creases, that are still stubborn to flatten after two weeks of hanging. Packing in a box would work much better in this case. The filling is very thin, not sure if this will be enough to keep me warm in winter.