Norrona Senja Flex1 Trackster Pants works great for all outdoor activities where you want lightweight pants. Norrona Senja Flex1 Trackster Pants works great for all outdoor activities where you want lightweight pants. Flex1 fabric offers excellent stretch, windproofness, breathability and effective moisture transportation. Since this fabric is woven, it also provides excellent durability without interfering with the mobility the 4-way stretch provides. The main material is a Bluesign approved 50Dx70D double weave 86% recycled nylon/14% elastane flex1 fabric (125 g/m2). Key features include soft elasticated waist, zippered back waist pocket, one open mesh side pockets, two hand pockets, reflex stripes and logo, zippers with gusset and elastic closure at the ankles. These pants have a technical fit with articulated knees that have been pre shaped for your posture when you are running.