Spring plunger;Adjustable patty thickness from 1/4 to 1 1/4;Patties measure 4 1/2 in diameter;Nonstick coating;Cast aluminum;Adjustable patty thickness from 1/4 inch to 1 1/2 inch;Patty diameter = 4 1/2 inch;Spring plunger button compacts the patty tightly then pops back for quick patty removal.;Non-stick coating for quick and easy clean-up;Heavy duty aluminum construction