The claws have springs on each finger at the top. So the pressure is variable. It's easier to go after a big item than a small one since the tension will be greater the further the claw is spread.

When you fill the machine, the trick is to pack the "prizes" down. That way they apply pressure to those surrounding. If you want a specific item, plan on spending multiple tokens to get it. It has to be loosened from the surrounding material.

And remember: They are designed to make margin. It is nearly always less expensive to go buy the item directly unless you are lucky and someone has loosened a higher value item previously.