I have a load of old stainless steel pipes to get rid of. I have listed from left to right the outer dimension (est) and thickness below:
Bends/Straights are 63mm x 1.5mm
Polished straights are 60mm x 1mm
Other Lengths are 54mm x 1.5mm
Since the photo I have also found some more short lengths which I think are 54mm including a 55-63mm reducer section.
£30 + Postage