If anyone is looking for a way to verify if your portafilter is stainless steel, I think you can try to stick a magnet to verify it. This one does not stick to magnets. So, I do not know what ever this is made out of. Also, be careful that there are many sellers who sells this exact same portafilter at very different price points like in here and here. There are many that claim this is stainless steel.