What is the ball joint special tool?

There all kinds of tools for Ball Joints; OTC Remover, Ball Joint OTC Ball Joint Separator KD Tools Ball Joint Separator OTC Ball Joint Service Set KD Tools Universal Ball Joint Separator OTC Wrench, Ball Joint Spanner KD Tools Ball Joint/U-Joint/Brake Anchor Pin Press OTC Master Ball Joint Adapter Set KD Tools Ball Joint/U-Joint/Brake Anchor Pin Press Set KD Tools Ford Ball Joint Cam Tool Sears.com