The PE Step Roller Tool from RPToolz is 195 mm long and constructed of Eloxed Aluminum (dyed blue) for use in rolling Photoetch (PE) brass, copper, aluminum and other malleable metal sheet, wire, and some shapes. The Eloxed (electrochemically oxidized) process creates a hardened anodized surface to resist scratches and wear.

The steps in the roller tool correspond to diameters of 4, 6, 8, 10, 12, 15 and 20 mm.

I found the tool capable of repeatedly making consistent-sized rings in wire and barrels in sheet.