Devia M4 are in-ear Bluetooth 5.2 TWS headphones with a charging case. The headphones support TWS (True Wireless Stereo) technology, allowing both earbuds to connect to each other and create a wireless stereo set. The portable case with a built-in battery not only allows for charging but also securely stores the earbuds in your pocket, bag, or backpack. Free your hands and listen to music or internet radio while working, walking, training, or driving. The Devia M4 TWS headphones are an ideal solution for users of smartphones, computers, notebooks, tablets, and other devices that support Bluetooth technology. They are compatible with most Android and iOS devices. The headphones also feature a microphone, allowing you to make voice calls with ease. The talk and music listening time on a full charge is about 300 minutes, depending on the volume level, thanks to the energy-efficient Bluetooth 5.2 technology.