How to connect with two devices simultaneously？ A. In the off state, switch on the device and enter pairing status. Turn on the bluetooth of the first device, search "M102" and click to connect. B. After the connection is successful, turn off the Bluetooth on the first device, the M102 will re-enter pairing status. Turn on the Bluetooth on the second device, search "M102" and click to connect. C. Turn on the Bluetooth on the first device, click "M102" and connect the Bluetooth headphones. * Note: Audio can only be played from one device at a time. If you want to play music from the second device, you need to turn off the music on the first device. The same is true when you call. How do I delete pairing records? Press and hold the "MFB" and "Volume-" buttons for about 5-6 seconds to delete the pairing record of the Bluetooth headphones. If the pairing record is cleared, the Bluetooth headphones cannot reconnect to the previously connected device, you will need to re-pair and connect. If the wireless headset can't work or any quality question, please kindly contact our support to replacement at any time. Long Battery Life The EKVANBEL bluetooth headphones equipped with a larger capacity battery, which can provide 45 hours of talking time and 400 hours standby time, and is enough to cope with a day's intensive use. You no longer have to worry about running out of battery during long journeys on the road. Hands Free Calling The Bluetooth headphones with mic supports voice assistant. Press and hold MFB for 1-2 seconds to wake up the voice assistant. Click the mute button to mute the call, and click again to unmute. Click MFB to answer and end a call. Reject call with press and hold the MFB for 1-2 seconds. Voice alerts battery low, connection status, mute/unmute status. Comfort and Convenience Comfort and convenience lightweight designed to fit your ears. Soft ear pad, and rotatable noise cancelling microphone adjustable headband allows you to find the most comfortable position to listen to songs, make phone calls and so on. Widely Compatible & Dual Connections Adopted Bluetooth V5.2 chip for faster connection and less power consumption. You can walk around your house with headphones on for moving up to 33ft/10m away from your connected device. It also enables us to connect to two devices at the same time for calls and music. Never worry about missing a call. Environmental Noise Cancellation The Bluetooth headphones has a unique structure that makes it durable. The noise-canceling microphone allows you to answer calls with impeccable clarity--even in noisy environments, including construction sites, call centers, or anywhere in life. Crystal-Clear Stereo Sound This wireless headphones delivers crystal stereo sound quality. You can feel the Vibration following the rhythm of the audio through the earmuff while you are lost in the immersive music. These headphones definitely give you a new experience about enjoying the vibration music. Highly Sound Quality A high-quality Microphone built-in enables you to one-click to answer a call, this Bluetooth headphone can pick up your voice exactly and block the noise from the surround, ensure the crystal-clear conversations even in noisy environment. Package Included 1 x Bluetooth Headphones(M102) 1 x Type-C Charging Cable(Cable only) 1 x User Manual Advanced Bluetooth Technology Bluetooth version: 5.2 Bluetooth chip: BT8925B2 Communication distance: 10 Meters/33 Feet