The New Balance women�s Fresh Foam Hierro v3 features a sock-like collar for a comfortable, secure fit and toe protection so you can confidently take on any trail. 8 mm drop: due to variances created during the development and manufacturing processes, all references to 8 mm drop are approximate. Bootie construction for a custom like fit. HypoSkin upper that adapts to the shape of the foot for a flexible and natural movement. No-sew material application. Vibram outsole provides maximum surface contact and multi-directional traction. Vibram is a registered trademark of Vibram S.p.A. All rights reserved.