What Our Gearhead® Experts Are Saying:"The Deer Island Jac-Shirt has become my default grab on cool mornings because the brushed cotton twill feels broken in almost from the start. It works just as well thrown over a base layer on a cold trail as it does worn on its own around town."The Filson Deer Island Jac-Shirt lives in that sweet spot between a shirt and a jacket, cut from a 9. 7-ounce brushed cotton twill that brings real warmth without the bulk of a true outer layer. Side hem vents keep your range of motion honest when the day gets moving, and the handwarmer pockets and button-adjustable cuffs make it as practical as it looks. It is the kind of piece that gets grabbed first and put away last.