Mountaineering Boots

Ice Climbing Boots
Generally the lightest weight boots, Ice Climbing boots are designed to allow the most freedom of movement when climbing. The boots' liner is built in, allowing the boot to fit better and lock down the climber's heel better. They are generally not as warm as other types of boots. These boots usually have both front and rear welts to accept step-in crampons.

Single Mountaineering Boots
Single Mountaineering boots look very similar to ice climbing boots. They are more insulated then ice climbing boots, which causes them to be heavier and less flexible. These boots may have a rear welt only, or a front and rear welt. Usually boots like these without any welts are used for backpacking. The best uses for these boots are one day or warmer weather climbs as you cannot remove the liners to dry them out at night.

Double Mountaineering Boots
Double Mountaineering boots are much warmer then single and ice-specific boots. They have either a leather or plastic outer-shell as well as a removable liner. Removing the liner allows the climber to dry it out in their sleeping bag during the night. These work well for multi-day expeditions in all but the harshest conditions.

High Altitude Boots
High Altitude boots are some of the warmest boots available, and are designed for extreme high altitude mountaineering. They usually have a built-in gaiter to keep snow and ice out. Because of their weight and size, these boots are only suited for the most extreme conditions. They can also be very costly.