Feature:1. Necklace 4 provides an ultra long music-listening experience. Up to 50-hour playtime allows you to charge your Necklace 4 once a week.2. Just 10-min fast charging can provide 10-hr music listening, making you music play on and on.3. Necklace 4 is featured with proprietary noise-cancelling algorithm and inline microphone, which helps reducing surrounding noise and providing clear voice in calls.4. Short press the Mode button "M" once to switch between Normal Mode and HavyBass Mode.Specification:Features:Necklace 4 provides an ultra long music-listening experience. Up to 50-hour playtime allows you to charge your Necklace 4 once a week.Just 10-min fast charging can provide 10-hr music listening, making you music play on and on.Necklace 4 is featured with proprietary noise-cancelling algorithm and inline microphone, which helps reducing surrounding noise and providing clear voice in calls.Short press the Mode button "M" once to switch between Normal Mode and HavyBass Mode.Necklace can connect 2 devices at the same time. Never worry about missing the calls from another phone. *Long press the button "O" and "+" at the same time for 2s to connect to the second device.Featured with IPX5 waterproof and inner sweat-resistant nano-coating, Necklace 4 is created to withstand the test of time, accompanying you through rain and workout time.Specifications:BT Version: V5.3Wir eless Range: 10mCell Capacity: 350mAhPlay Time: Up to 50 hoursInput: Type-CNote:1.Due to the different display screen and light effect, the actual color of the item might be slightly different from the color showed on the pictures.2.Please allow a little measuring deviation due to manual measurement.Package List:1 * Neck EarphonePackage List:1 * Neck Earphone