It is, but then Astro 3 (versus 3E) intended for a more heavy duty charging tasks including support of 9V/12V charging for laptops.
Btw, for benefit of others as a general comment, Anker is probably one of the few companies that is VERY honest about capacity. When you deal with External vs Extended batteries the capacity rating is not the same. Extended battery that goes into your phone supposed to be rated to that exact capacity based on a sum of internal cells. That battery goes into direct contact with electronics in your phone without a need for any conversions. External battery operates through USB bus and goes through a few conversions with penalties. As a results, with any External battery you actually get about 70% of the actual capacity that you Internal battery can benefit from. And the reason I admire Anker because they actually state that in their manual - approximately 30% of capacity will be lost.
This is not just applicable to Anker, but any other External battery vendor.
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