And this type is another C-type for faster off-the-car valve removal. Not the cheapest but you don't have to clamp the head down when working out of the car, and the large size of the parts of this one makes it easy to hold and work with you whole arms. Can't be used on-car.
The simple lever types takes some time to relocate from valve pair to valve pair, put in the rag under the chamber, and you need some clamping of the head to the bench to use them off-car. Unless you are reeeally strong, you can't hold the head down and work the lever with strong springs, and even if you could, you would not have a hand free to remove the keepers. That is why shops use the C types; speed.
Proform 66832: Heavy-Duty Manual Valve Spring Compressor | JEGS