The seller claims up to 0.8mm sheet metal, while the manufacturer on the included card states 1mm. The truth is that it cuts easily through 0.65mm and relatively through 0.8mm, but the problem lies in the quality of the materials. Although the idea is fantastic, the metal holding the wheels, as well as the wheels themselves, wear out with minimal use. The gears inside have a very loose connection, causing the teeth to easily skip and potentially break if not careful. It's a shame because the idea is truly brilliant and it works if someone were to make it with better quality and durability, it would be perfect.