3031B is designed to mount professional cameras like Canon C100/200/300, RED, Komodo on the gimbal. The extended plate adds 40mm to the plate compared to the original camera plate. You can add Counterweight Kit 3125 to the rear to balance the stabilizer, attach Lens Support 2850 to protect the lens mount, and Focus Motor Component 2851 to connect the DJI focus motor when the lens is mounted on a large camera body or a camera with a battery grip. In addition, a 1/4”-20 threaded hole on the bottom can be used for adding the Counterweight AAW2284 or AAW2285 for balance.