The best list of air-gaps I've seen comes from an archaic book in German published in the 1930s. Here's the link: http://www.kronjaeger.com/hv/hv/msr/spk/index.html Rhys Sage SagePhotoWorld.com America's favorite photographer. _______________________________________________ Tesla mailing list Tesla@xxxxxxxxxxxxxx http://www.pupman.com/mailman/listinfo/tesla