- Phone pricing;
- Where and when it was bought;
- Expiration date of guarantee;
- Year of production;
- Hardware.
Not with all models complex info is available but in most cases you can check basic info when buying phone from second hand.
Site is available in 4 languages: English, German, France and Polish, it have simple design and it's fast and (in many cases) free, so you can easy check some basic information.
It was created by people I personally know from some time now and is offspring of their bigger service for unlocking simlocks.
As I wrote earlier service is mostly free of charge but for some models there are fee - it depends on producers policy.
I recommend this site with all my experience.