We recommend a certified charging block with an output of 5 volts and 1 amp to use with both the Pearl and the Lunar.
The charging block that comes with your mobile device is safe to use for charging your Acaia scales. If you plan on purchasing a charging block, we recommend purchasing from a big box store like Best Buy or Target and avoiding purchasing from Amazon. Some charging blocks on Amazon have forged certifications and could potentially damage your scale's board and battery.
There are a lot of "fast-charger" blocks sold on Amazon that have a high amp output that works fine for charging something like a cell phone quickly. These blocks are not the best for our scales. To get the most life and use out of your scale, use a charging block at or under the recommended specifications.