There is no manual or datasheets in the package, so you need to go to their website to download them. The quality is pretty bad as you would expect. I haven't used most of them, so I can't comment on their functionality. There are many different types of sensors, so there are many small projects you can use them for. Once you find a project that you want to turn into something more serious, I think you need to replace the sensor(s) with something better.
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