881 series threaded sight flow indicators

881 Series are a range of industrial double window sight glasses with either BSP or NPT female threads in sizes from ½” up to 2”. Available in Cast Iron, Carbon Steel or Stainless Steel and a choice of soda lime or Borosilicate glass there are options to suit most process industry needs. They come with a choice of a plain drip tube which is ideal when you need to inspect for bubbles, colour or quality of the media, if rudimentary indication of flow is required a flap or spinner can be provided. Primarily designed for low viscosity liquids or gases (drip tube and flap only, not spinner type), they can be mounted horizontally or vertically.


  • Pipe Sizes: ½” to 2”
  • Connections Styles: BSPP or NPT
  • Body Materials: Cast Iron, Carbon Steel or 316 Stainless Steel
  • Glass Material: Soda Lime or Annealed Borosilicate Glass
  • Seal Material: Klingersil or PTFE
  • Rotor Material: Acteal or PTFE
  • Flap Material: Stainless Steel
  • Pressure: up to 40 Bar depending on version
  • Temperature: up to 250°C
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