Meat presses do exactly what their name suggests. They take meats of several different thicknesses and flatten them out to create uniformity. The desired thickness can be adjusted via a thickness knob. Feature such as a non-stick coating on the upper and lower platens and a swing-out bottom tray allow for quicker, easier pressing. You will want to take a look at the actual press dimensions to help get a good idea of how many pieces of meat can be pressed at once.
As a side note, you will want to avoid sending bone-in meat through the press. If the bone is thicker than the indicated setting, the press could shatter the bone or damage the press itself.