You love your old boots, but their liners are beyond packed out, their buckles are barely hanging in there, and what used to be a stiff 130 flex is starting to feel more like a squishy 90. It's time for an upgrade and K2 has joined the boot making game since the last time you were in the market for a new boot, so you can expect good things. Sitting at the top of K2's line of big mountain freeride boots, the Men's Spyne 130 Ski Boot is its most hard charging offering with a stiff 130 flex, progressive fore and aft flex, and lasted Intuition Precisionfit liner. K2 has expanded its offering this season by offering the Spyne in three different last widths. This particular version of the Spyne sports a medium wide last of 100mm.The Spyne incorporates much of the same technologies you'd expect to find on a high end boot: four micro adjustable buckles, a cinchable power strap, adjustable canting, and an adjustable forward lean, but where the Spyne really differs is with what K2 calls its E3 design philosophy. The E3 design philosophy combines a carbon infused spine that runs down the back of the cuff to the heel of the shell to add an extra bit of rigidity to the boot the carbon spine allows for less material to be used in the shell and cuff, resulting in a lighter boot that's also easier to work with in the shop. In addition to the Powerfuse Spyne, K2 also developed a connection between the shell and cuff by eliminating the use of rivets. The interlocking connection not only allows the boot to flex forward more naturally, but it puts less stress on the rest of the boot and offers a smoother ride as a result.