Few rules:
Is it made in China?
Does it have China Exported logo? (looks like European CE logo, buts not in closer look)
Is it super cheap compared to more reputable suppliers?
More time you answer yes, less quality it has...
And im not saying this is end of all list, you do time to time get shit made in western countries as well..
Im also not saying all super cheap from china is crap. I often buy super cheap stuff from ebay, etc.