This is a battery (model number HWBBJ1) for SoftBank Pocket WiFi, models 501HW/502HW. It is fully compatible with other mobile router battery packs (HWBBN1/HWBBK) from SoftBank and Y!mobile, and can be used directly. This is a "nearly unused" item that was kept as a spare and only had its power-on status confirmed. It looks to be in very good condition and should work without problems, but as it has been stored for a long time and I don't have an environment to test it, I honestly don't know how much remaining performance it has. Please purchase on the understanding that it is basically without warranty. The battery itself will be shipped via Mercari delivery with free shipping. I will take all possible precautions when shipping, but there is still a possibility of unforeseen circumstances. In such cases, I apologize, but please coordinate with the shipping company. (The seller cannot provide compensation) *Please read the notes on "free shipping" in my profile before purchasing. By purchasing, you are deemed to have understood the contents described.