1. listening extension cable feature is designedo be more convenient, without the need for a long-term earphone ear. 2. ringing reminder function.3. intelligent voice reminder 4. Switch 5. power display; one to tow 2, can connecttwo mobile phones simultaneously ; single-ear Model:K53 Bluetooth Version: V5.0 ransmission Distance: 10M Transmission frequency: 2.4 ghz Charging voltage: DC5V Charging time: less than 2 hours Talk time: About 10 hours Music time: About 10 hours Standby time: 150 hours or more Fuseage size: 56(long)x26(wide)x14(high)mm Support for the Protocol Handset handfree A2DP AVRCP colour: black Material: plastic Size: 56x26x14mm Package Contents: 1 x Wireless Bluetooth Headset 1 x USB cable 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.