The 550 Pocket Handheld is built from UltrAcool Light Mesh which provides comfort, durability, and breathability. Soft perimeter binding eliminates any abrasion on the hands while running. This handheld utilizes a non-slip securing strap which stays out of the way on the backside of the hand. The 4-way stretch mesh pocket is 80% nylon and 20% spandex for capacity and durability. The zippered compartment is designed with no seams allowing the pocket to stretch outward to carry more items and keep those items from moving around.