Emin Mammadov wrote a review of ETON Boost 4200 Portable Phone Charger on July 30, 2014
Familiarity: I've used it once or twice and have initial impressions
I was a bit disappointed. Tech specification - 4200mAH, but in reality I have tried it twice. First time: full charging of Galaxy S2 (1650 mAH) and next Galaxy Note 3 (3200mAH), Note was charged up to 40%. I thought, it might be simple electronic glitch. Tried to charge Note directly- outcome 90%.
So, what does it mean, Boost 3000 instead guaranteed 4200mAH?
In addition, ETON Boost 4200 Portable Phone Charger has had a stamp on the pack "precharged", but I've found it in fully discharged condition.