The Photon Pants are very warm, PrimaLoft® synthetic insulated pants, designed to provide greater freedom of movement in extreme polar environments. Using a combination of Pertex® Microlight and 100% Ripstop fabrics, the Photon Pants are extremely durable and are designed to withstand expedition abuse. Reinforced knees, seat and kick patches provide high levels of freedom of movement, and full-length YKK side zips make the pants easy to take on and off when wearing crampons. A expedition fit means the Photon Pants can be worn as an outer layer in conjunction with the Expedition Jacket in the harshest environments. FIT NOTES (Expedition Fit) This product is designed specifically for use in extreme conditions. It is an winter-weight piece and is oversized to accommodate multiple layers.