I was looking for attractive hit and miss vents - white and preferably an attractive finish rather than tatty plastic. I could try spraying a metal version, but paint would probably scrape off when the mechanism operated. Then I saw these:
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Only "special" thing about them is the "patent pending triple action filter" in the middle. The system is interesting but very overpriced. Often these "radical" new things turn out to be a piece of mineral wool or a bit of sponge! Any idea what this filter might be? - the picture in the PDF is too small to see. Suppose I could try to find an outlet that supplies these and have a look ... I then might not need a hit and miss vent and could fit a standard one that is more easy to find in an attractive finish. Simon.