Bluetooth 5.4 and Auto Connection: Wireless earbud adopt advanced bluetooth 5.4 technology. You can get 2x faster transfer speeds than Bluetooth 5.3, more stable transmission, lower power consumption and ultra-low latency listening experience. Open the lid of the charging case, the bluetooth earphones can be automatically connected to the previous paired device. The wireless earphones are compatible with almost Bluetooth-enabled devices such as iOS, Android cellphones, tablets, laptops, TV, etc