1. Why two earphones cannot be connected synchronously Answer: Because both earphones of LP40 contain separate chips. Very few earphones are out of sync on the first use after leaving the factory. You only need to do a manual sync to fix this problem permanently: Please delete the bluetooth of the LP40 name on the mobile phone → turn off the bluetooth of the mobile phone → put the earphones back into the charging compartment and close the cover → wait for a while and then take out the two earphones at the same time, please do not press the touch position and please wait for 10 Turn on the mobile phone Bluetooth after a few seconds → find the LP40 Bluetooth name on the mobile phone and make a pairing connection.