A Roadmaster Crossbar-Style baseplate accommodates Roadmaster tow bars and accessories by utilizing the crossbar and/or quick-disconnect system as a mounting platform. If you are using a Sterling or a car-mounted tow bar, you need this style of baseplate. To use this baseplate with a direct-connect style tow bar, such as the Roadmaster Nighthawk, you will also need to order a Quick Disconnect Crossbar (Roadmaster part # 910021-00, Sold Separately).