What is the difference between the Pro Series and Tuner Series Ball Joints?

The Pro Series Ball Joints have the adjust screws located on the bottom of the top plate for much easier adjustment. They also have more clamping force. The Pro Series Ball Joints are larger, which spread the weight over a larger surface area resulting in longer life. These ball joints also feature revised casings allowing for a greater range of articulation as well as a revised dust boot with a prefabricated crease point to enable it to maintain a better seal. The Tuner Series Ball Joints have the adjustment screws located on top of the top plate, which cause for a more difficult adjustment.