The Wella "Identical to Nature" Perm rods were introduced in the late 1990's. They are probably considered limited edition or maybe even vintage.
They are designed to deliver more volume by giving alternating bends in the hair.
I like the closures on these. I do not have to worry about losing the closure band. I have about four different sizes in this design. I would probably use these perm rods in the top and crown areas. Most people want more volume in those areas.