Thomann CBT 10

Let me be clear, this battery tester works fine, and the price is perfect. However, if you do a lot of battery testing, you will want to find another product. On this one, the slider moves rather difficultly, and the display really only shows you a simple gauge, as you can see in the pictures.
In conclusion, check your use-case before buying. If you will be using this every day, you might want to look for an upgrade.

Nice little gadget, comes very handy if you use often wireless gear. It can save you lot of money showing you that many used batteries are still ok. not super quality made but do the job.