Note added on 2025.12.25 Regarding the battery life, it seems some people are concerned, so I will conduct a battery test. It will take some time (as I need to monitor until the amplifier's power runs out), so please allow me some time. I will write the test environment and results here by 12/28. (Of course, there's no problem if you purchase it without waiting for the results.) ＜I do not accept price negotiations. Thank you for your understanding.＞ Thank you for viewing. I purchased this in December 2016 and used it, but I haven't used it for about the last two years. (I have been charging it regularly during this time.) Also, I tested it, and it can be used while charging. (This product has two micro USB ports, one for charging and one for data transfer.) I performed the tests in the following environments: ・Android smartphone (SHARP AQUOS R10) + PowerAmp (Image 5) ・Custom-built PC Windows 11 + SONY Music Center for PC (Version 2.7.2) (Image 6) ・iPad mini (6th generation) + Spotify (No image) The sound is playing normally in all environments. There was no scratchy noise when turning the volume knob. ＜About Accessories (Image 4)＞ Walkman(R) digital cable: Included Xperia digital cable: Included Micro USB cable: Included (but from another company) Silicone band: Included Sheet: Included Please note that the box and papers are not included. (As a bonus, I will include a USB Type-C adapter (converts micro USB to USB Type-C).) ＜About Packaging＞ The amplifier body will be placed in a zip-lock bag and wrapped in bubble wrap. Other accessories will be placed in zip-lock bags. The gaps will be filled with old newspapers, and then sealed. ＜About Shipping＞ I will ship via Takkyubin Compact. If you would like to specify a delivery date and time, please let me know in the comment section after purchase.) Thank you very much.