Ever seen one of these? Pictures at; http://derosaweb.net/aviation/cambridge/filter. It seems to have a large ID at one end and a much small ID at the other end.

- What is its function?
- What airline does it go with?
- Which direction should it point?

Back Story: A friend (IA/A&P) was working on the airlines of a glider. From what I gather there is a Cambridge CVS-50 installed. There is also a Winter vario installed. He removed all the airlines from instruments before noticing this hard plastic component until it was too late. Now he is lost as to what to do with it.

Thanks, John OHM Ω