The new K2 Spyne 120 is an excellent boot for the aggressive skier who has a medium to narrow forefoot and medium to narrow leg shape. K2's Energy Interlock Construction integrates the upper cuff and lower shell to have a smooth a natural flex. The PowerFuse Spyne enhances lateral stiffness for more responsiveness when you are really flying down the mountain and improves the forward flex and rebound for added control over your skis. The Spyne 120 has plenty of thermoformable material in the liner that allows it to be heat molded for a more customized fit. If you want power and responsiveness the K2 Spyne 120 is the boot for you.