The ProMediaGear GT1 converts your ball head into a gimbal head. It is a more compact and lighter alternative to the Katana Gimbal Head. It attaches via Arca-Swiss style adapter (already included) in vertical or horizontal fashion (to better balance the weight center point).
If you don't have an Arca-Swiss ball head (or compatible) then you can use the 1/4inch20 threads inside the mounting foot to mount your quick release plate. There are total of 3 1/4inch-20 threads on the foot giving you ultimate flexibility. Your lens has to be equipped with a compatible Arca style plate and to mount the lens you simply slide it into the clamp adjust balance and lock it down tightly.