A smart, insulated flannel shirt that will soon become your everyday essential. The Sinclair Insulated Flannel has all the trappings of a regular ol’ flannel button-up, but it has a secret weapon you can barely notice from the outside: It’s stuffed with 40 grams of Spaceloft™ micropuff insulation for added warmth. Brushed tech flannel on the outside adds warmth and comfort and a smooth taffeta lining on the inside and quick metal snap buttons make the Sinclair easy to take on and off.