A new Sheaffer enthusiast to the site but I have used the pages many times.
I have a Sheaffer fountain pen that has a short inlaid diamond steel nib. The cap is the short type with the white dot.
In many respects it would be a standard imperial but the barrel and cap are "fluted" stainless steel.
I wondered if it could be a 506, either Imperial or Triumph.
Any ideas would be appreciated.