Sorry, I'm not a native English speaker. What I meant was that the newer, improved design doesn't use steel pipes any more. Instead, solid and rectangular shape

Sorry, I'm not a native English speaker. What I meant was that the newer, improved design doesn't use steel pipes any more. Instead, solid and rectangular shaped steel is used that can't be cut with a pipe cutter any more. The page behind the link should make it clear. You can filter it by "Eckig" ("rectangular") to see the ones I mean.