The specification
  Orde No.     Outer Diameter       thickness       Hole dimater     Segment number

  CH-0150           230mm                1.6mm               25.4mm                2T
  CH-0151           250mm                1.6mm               20.0mm                2T
  CH-0152           255mm                1.6mm               25.4mm                2T
  CH-0153           255mm                1.6mm               25.4mm                2T
  CH-0154           255mm                1.4mm               25.4mm                2T
  CH-0155           305mm                1.6mm               25.4mm                2T
  CH-0156           305mm                1.8mm               25.4mm                2T
  CH-0157           305mm                2.0mm               25.4mm                2T
  CH-0158           305mm                2.5mm               25.4mm                2T
  CH-0159           355mm                2.5mm               25.4mm                2T