I'm browsing around in Chinatown yesterday checking the Vietnamese
packaging for the Sen and Lai characters. Its a mixed bag of
characters with or without the grass radical. There are plenty of
large pretty boxes of various teas in the 300g range which makes the
tea more expensive which I usually ignore. I found a brand from
Taiwan called SunLong. It was discounted at one of the tourist stores
and you can't go wrong with tea from Taiwan except for my last and
only batch of Oriental Beauty. There is a thumb press on the large
round lid which has to be pressed to slide on and off. It can't be
forced otherwise. It took awhile to figure out the patent principle.
The thumb press seats a small rubber seal which allows air to rush out
when capping and in when decapping. There isn't enough clearance
between the lid and container for the air to escape otherwise. I've
talked about the partial vacuum created by volume displacement from a
lid in other posts. The green tea comes in a nitrogen pack which I'll
break one of these days. The packaging is hard thin brittle plastic
which I don't think would cause a problem even in hot climates.

Jim