Must admit, had a set for years and never really used them. Didn't see much improvement with them to be honest. In any case it's a dead-set shame turning a wonderful planet into a garishly-coloured nightmare. OK, Mars with an orange filter might be acceptable!!
Numbers are dwindling now as I've gradually 'converted' them for use with some weird & wonderful experimental filters, courtesy the Surplus Shed. Still have the glass rounds, might make a good mobile sometime...
Cheers -