Ergonomic elements have been added to all aspects of the AirPro. The contoured seat and seat backs have been designed with increased comfort in mind. Multiple-sized holes in the special foam padding produce varying densities to provide extra cushioning along the spine and under the legs while comfortably supporting the sit bones. The flexible back rest features a cutaway for spinal support and a more rounded design to conform to your back; the seat's leg lifter area has a softer edge and is more contoured to your thighs. The Air Pro also features carefully selected material over the perforated foam, greatly improving ventilation so you and your seat breathe and dry out quickly. This seat fits the Ride 115 and 135.