What does it mean when the bowl is tuned to "perfect pitch 440hz"?
440hz tuning is the international standard for tuning instruments. This means that the middle A note resonates at 440hz and all other high and low notes are tuned at 440hz. So, when you see a bowl tuned to perfect pitch at 440hz, it does not mean that the bowl resonates at 440hz. It means that the bowl is tuned to a middle A tone that resonates at 440hz.
What does it mean when the bowl is tuned to "perfect pitch 432hz"?
432hz tuning is the same concept as 440hz tuning described above, but instead of center A resonating at 440hz and all other notes being tuned to 440hz, center A now resonates at 432hz and all other notes are tuned to 440hz. Since center A is tuned 8 hz lower than standard tuning, all bowls tuned to 432hz will be slightly lower. Some people consider this a more pleasing tuning.