From Fizik:

Vento Overcurve X3 is an XC racing shoe designed and created to deliver its core functions: to fit precisely, protect you and transfer watts efficiently as you power through the race tape.

Overcurve is a shoe construction featuring a staggered collar that wraps around the ankle, tracing the natural misalignment of the ankle’s two bony protrusions: the lateral and medial malleoli. The result is an asymmetrical shape, with the throat of the shoe curving over the foot from its outside to its inner side. The closure is simple and secure, powered by a micro-adjustable BOA IP1 dial.