Product name: Roller Bluetooth remote control Charging compartment capacity: 180mAh Bluetooth version: V5.3 Remote control capacity: 30mAh Transmission distance: 10 meters Usage time: about 24 hours Charging interface: Type-C Input current: DC5V Product size: 39 x 33 x 23mm Product functions: Roller page up and down, slowly slide the roller up and down, adjust the length, turn the e-book left and right, turn off the screen, like, return to the main menu to take photos and videos, skip songs, pause playback, increase and decrease volume Color: Black Material: ABS Package Contents: 1 x Roller Fingertip Ring Remote Control 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.