even with heavy use

The shell is built with dual plastic layers

the Project 91 is an excellent choice

three with YKK zippers and one with Velcro closure

lange standard iso5355 alpine soles 1 kit MDXOne even with heavy useWith Lange Standard ISO5355 Alpine Soles, you'll keep your ski boots fresh for longer. These are replaceable toe and heel pieces that fit boots with the traditional alpine norm according to ISO 5355. Perfect for those who want to replace worn soles and extend the life of their favourite boots. They are easy to install and come in a complete kit with two toe soles and two heel soles everything you need to do the job yourself. Lange Standard ISO5355