1. The built-in battery lasts up to 16 hours. 2. Keep pairing with 2 wireless devices at the same time. 3. The built-in microphone can be used to answer hands-free calls. 4. The latest noise-cancelling technology provides excellent call quality. 5. Compatible with most wireless-enabled devices such as smartphones, tablets, laptop and computer. Pair with phone/mp3/tablet etc, turn your old car stereo/house stereo/3.5mm wireless wired headphones. Wireless version: 5.0 Frequency range: 2.4GHz Output power class: class2 Wireless Mode: HFP//A2DP/AVRCP Wireless Range: than 33 feet Battery: 250mah Working current: 15-20MA Charging voltage: DC/5v Charging current: 150MA Product size: about 50x50x20mm Colour:As Shown Material:Plastic Package Contents: 1 * Wireless Receiver 1 * 3.5mm Male to Male Connector 1 * 3.5mm Audio Cable 1 * Type-C Charging Cable 1 * English User Manual 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.