Battery Case Attachment For SONY MD Walkman MZ-N10 ?Charging and data sync) Three-in-one battery case (USBC charging, music transmission, external lithium battery case) Lithium battery can be replaced freely Dear customers, before buying, you need to know Please check first, is the N10 built-in battery healthy? If your N10 built-in battery is very unhealthy, then our battery box may not work properly (easy to overload). It is recommended to replace the N10 built-in battery first Second, will the motor in the machine be short of oil? (Because most machines have been used for more than 10-20 years, the laser head motor may need to be refueled, and some maintenance and maintenance are required. The symptom is that the noise is louder than before when cutting songs, or overload causes shutdown) If you feel that the machine noise becomes louder when cutting songs? It is possible that you need to refuel your player motor, which will also cause the battery to overload and the machine will shut down. Create the illusion that the battery is consuming power quickly. Every time you need to turn on the machine through the switch on the back of the machine. If this phenomenon occurs, your machine may need simple maintenance and maintenance. If you have any questions, please continue to leave us a message Thank you very much ?In bulk, WALKMAN not included. Just the battery and battery case.? USBC charging port with charging indicator light This is a battery case that can charge and transfer data. It has a built-in lithium battery. 3D printing requires production queuing time, usually we ship items in about a week Dear customer, I'm sorry, because 3D printing is not as perfect as traditional plastic products. If you receive the items and have any questions, please leave a message to me. Please don't worry, the items are guaranteed, thank you