Filson Insulated Jac Shirt | Otter GreenFilson's Insulated Jac Shirt is crafted from water resistant Cover Cloth with a generous cut so you can layer comfortably. This outer layer shirt has lightweight insulation for retaining body heat without weighing you down, allowing for maximum mobility. The sleeves and body are lined with dry finish Cover Cloth to help with easy on off over layers, while the snap front closure helps keep the wind and rain out and can be easily maneuvered even with