Machined from AISI 304 STAINLESS STEEL, with four adjustment points, alloy 304 is an austenitic stainless steel. It is essentially non-magnetic. Its lower carbon content relative to Alloy 302 provides better corrosion resistance. It is the most common form of stainless steel used in the world, largely due to its excellent corrosion resistance and value. It contains between 16 and 24 percent chromium and up to 35 percent nickel, as well as small amounts of carbon and manganese.How hard is this material? Its tensile strength ranges between 460 and 110 MPa, its elastic modulus is 190 – 210 GPa, it has a Brinell hardness of 160 – 190 HBW, it can experience an elongation or elongation of up to 60%, as well as a area reduction of 70%. With polished and engraved finish, internal diameter 33 millimeters, x 28 threads (TPI), external diameter 42 millimeters, adjustable with 12-tooth sprockets, making it the best adjustment option for our Trabocchi hubs