How do I connect to the LTS21 with an Android phone quickly?
①Turn on the Bluetooth of the phone. Press each ear device for 3 seconds to activate it and turn on your phone’s Bluetooth. 
②Select our headphones device name in the Bluetooth interface. The mobile phone will connect to it automatically.
The headphone related
LTS21 The user manual How do I connect to the Remote Controller device with the LTS21 quickly? How do I connect to the LTS21 with an IOS phone quickly? I sweat a lot while work out, will this damage the headphones? BR80 Upgrade Guide EVO21 Upgrade guide How to upgrade LTS21? OTA upgrade Guide