MHS: Modular Hitch Base. The MHS base is offered in multiple sizes. This 3+1 Base is engineered to carry 3 bikes with DUO Trays and 4 bikes when you get the DUO Add-On. It features tilting capabilities for convenient rear of vehicle access with an easy-to-use outboard handle. With its Hitch Tighter System, the rack has a rock-solid hitch connection and it is fully assembled and easy to install on your vehicle. This is the future-proofed hauling solution from Saris that is highly customizable for bike and gear carrying accessories.