Those things work great, but a couple comments:

1: OP asked about Power Adapters, these are just plug adapters, which is a different sort of beast. That said, just about everything these days is dual voltage, so a real power adapter is often not necessary. Not remembering the full OP I'm pretty sure they're asking about plug adapters and not power adapters, but I could be wrong.
2: OP is going to Asia, IME, first most hotels will loan you one for a couple days, and you can get them in electronics markets for almost nothing. I bought about 6 of these for every plug type in the countries I frequent for less than $1 each and I've used them on every trip without fail.