These are from Singapore. I bought 4 of them, can't use all 4, and due to my coming move I'm letting them go. Rest assured the other pair will be put to good use (I have a slight preference for the aesthetic proportion of the other pair)!
They do wonders for smoothing out rough edges of tea and deepening flavor. Aroma becomes more intense although maybe some high notes get lost. I don't brew many teas with high aromas in there so I can't say for sure, but I've brewed a green 'aged' baozhong, a youngun only 10 years old, that actually had some high notes and those aspects of the aroma were a little muted but the fruitier aspects were enhanced. I probably wouldn't pair them with a nuclear green tgy/gaoshan.
Oh, pm'ed you as well.