Symbols: Double-arrow circle enclosed "10" on electronic appliances
That's a Chinese RoHS / recycling indication: Under RoHS 2, manufacturers must indicate dangerous chemicals inside on the outside. The number in the circle is an indication for the "Environment Friendly Use Period", the period in which it's safe the contained substances will not leak out. 

10 in your circle means that it's pretty safe that for 10 years, no RoHS-critical substances will leak out.

https://www.electronicsweekly.com/blogs/directive-decoder/china-rohs/china-rohs-new-efup-guidance-2007-03/