Keen Independence Internal Met Guard BootsASTM CSA Certified internal metatarsal guard is flexible and lightweight for comfort, but hardens and protects upon direct impact. Assembled with pride in Portland, Oregon using the finest materials from around the world. Left and right asymmetrical, non metallic carbon fiber toes offer unobtrusive fit and are 15% lighter than steel. Featuring nearly 100,000 air bubbles per cubic centimeter infused into the midsole, KEEN Luftcell PU provides