AT skis, or Alpine Touring skis, are designed for both uphill and downhill skiing. They feature a lightweight construction that allows skiers to ascend mountains efficiently while still providing stability and performance on descents. These skis are typically paired with AT bindings, which enable the heel to lift during ascents and lock down for downhill skiing. AT skiing combines elements of cross-country skiing and alpine skiing, making it a versatile choice for those who enjoy exploring backcountry terrain.