2 pcs of bent round bar from 5 mm stainless steel Aisi 304 4 plates of 3 mm stainless brushed steel Aisi 304 Bolts, nuts and washers are stainless A2 These brackets are made to last forever and are a safe way to transport the very young children. They are therefore made of stainless steel with through-going bolts, a 3mm stainless steel back plate, and washers and lock nuts. This is the only proper way to secure the bracket, as ordinary screws will be torn out accidentally.