Kentucky Horsewear Deep Fetlock Boots BlackThe Deep fetlock boots are made from a sturdy TPU shell with multiple ventilation holes and a large ventilation triangle. The interior of the boots is reinforced with an additional layer of TPU to withstand heavy abrasion when the hind legs are in motion. The Deep fetlock boots feature an extended 3D spacer lining that covers the inside of the fetlock area and protects against cuts and other injuries. The exterior of the 3D spacer is reinforced with