The body is made of a blend of aluminum, copper, and possibly expensive and very hard titanium. I'm not sure, but I imagine if you search for it on the internet, you will find it... It is EXTREMELY LIGHT! When you hold it in your hand, you have the feeling that it is a plastic toy and that it will break with a single hit. However, it is not like that, and I am sure that it is comparable to the steel ones. I give it 4 stars because it is a bit expensive. Those who want an excellent heavy-duty classic padlock for security should buy the classic Abus 888/95 (large 95mm) and Abus 888/85 (medium 85mm), I have both, in fact, they are slightly cheaper and I highly recommend them.