La Sportiva developed the Aequilibrium line to strike the perfect balance between durability and weight to satisfy modern alpinists, and the Aequilibrium ST GTX situates itself smack dab in the middle of the line. Lighter than the fully-enclosed hightop version and more durable than the LT, we've found that there is truly no downside to this model. The GORE-TEX Performance Comfort lining keeps you dry from dawn till dusk, and the unique double heel supplies loads of braking power over arduous descents.