Royal Robbins comfortable Hollow Care Flannel is engineered to keep you warm without weighing you down. It's constructed from lightweight ThermoTech hollow core polyester fibers, which trap air for greater insulation. This fabric is also wrinkle resistant and has UPF 50+ protection. The Vintage plaid shirt is 5.5 oz 100% polyester and features a contemporary fit. It has roll up sleeve tabs for a versatile look and a shirt tail hem for some classic style. This hip length shirt even has a chest pocket with a button closure for a secure place to secure your essentials.