[Boatanchors] air-flow switch

[CLIVE COLLINS]

Good evening Gentlemen,
  I am seeking an airflow switch that will detect air movement into an HF linear air chest for two 4CX350F tubes. The one I am looking for is a simple low torque microswitch with a steel wire operating arm and a small sheet metal blade on it.
  Cant find one in any surplus outlet and if any one has a spare switch I would be happy to discuss a price for it and postage.
  Many thanks and kindest regards,
   
  Clive GW3WEQ