Convert your cartridge to a Bluetooth cartridge player and you can immediately use the 5.0 Bluetooth program. Used for your car or home system Supports Bluetooth answering/making calls Supports stereo music playback, audio formats: AAC, MP3, SBC, stereo Supports Bluetooth 5.0+EDR backward compatibility: Bluetooth devices such as 4.2, 4, 3.0, 2.1, etc The cartridge comes with a built-in lithium battery that can be charged Note:Different Batches May Have Differences In Product Appearance, Color, And Printed Characters, Which Will Not Affect The Use Colour:Black Material:ABS Package Contents: 1 x cassette player Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.