Fjallraven's Keb Pants are made from stretchy, recycled organic fabric G-1000 providing greater freedom of movement and durability. The knees are articulated and have additional seams that's why we don't blow them Zip vents and extra long fly help keep you cool if it gets hot. Fjallraven also included adjustable cuffs with boot hooks to prevent grass, dirt and snow from getting into your socks.