This is an Edelrid Crampon Bag. It is a lightweight bag designed for safely storing and transporting crampons and other ice climbing equipment. 
It features durable materials like Hypalon and ballistic nylon to protect other gear from sharp points. 
Mesh inserts promote quick drying of wet equipment. 
The bag has a large opening with a full-length zipper and a strap to cinch down the contents. 
A large attachment loop allows the bag to be connected to the outside of a backpack.