A particularly breathable underrug in air mesh fabric. The high tech material provides good ventilation and a wicking away function, at the same time as keeping the horse warm. Likewise, the air mesh fabric can prevent heat from building up. With a simple chest T-fastener, and 2 elastic touch tape fasteners both in the shoulder and hindquarter areas for ease of attaching to all Waldhausen Economic, Comfort and Premium outdoor rugs. This underrug is ideally suited for greatly fluctuating temperatures.