Theory 100% wool (with satin lining on sleeves and in side pockets for comfort). Grey, plaid button up with two side pockets and two front chest pockets with flaps and buttons. No flaws. Because of the side pockets it's technically a shacket (cross between a shirt and a jacket) but despite being all wool outer shell, is quite light weight. I wear a small but this small is roomy enough for me to wear a medium weight sweater underneath.