Men's Thermic BibLayering Position Insulated Outerwear Use The Thermic Bib is purpose built for bitter cold days in the treestand or blind and is the coldest weather component of the First Lite whitetail outerwear kit. This is ideal for full winter sit in hunting both on a treestand or high seat, for rifle or bow.. no matter if you are after wild boar of persisten with your predator control.. It's built using 170 gsm PrimaLoft Gold insulation, sherpa fleece lining,