?How to pair the headphones to your device? 1. X1 Headphones not only support both iOS and androidsystem, and also most of other Bluetooth-enabled products. 2. Please turn on the Bluetooth on your device at first. Then press and hold the middle button (multifunctional button) on the headphones until hearing "power on", the red and blue LED indicator will also flash. There you will see "X1" on the Bluetooth list of your device. You will be able to get them connected by clicking the pairing name "X1". 3. X1 can remember previously paired devices. Hence, you don't need to go through the pairing steps every time. Next time, you will only need to turn on the headphones. If you have any pairing issues, please do feel free to contact us. ?About Comfort Fit? To fit for more people's needs, we have 3 pairs of different sized ear tips (S, M, L) and ear hooks inside the package. Besides, there are also cord clip and clamp provided for you to fix the cable on your clothes and adjust the cable length to ensure a better fit. However, there are still some customers feeling not comfortable and suitable. Please do not hesitate to reach us then. Your advice and opinion is always the most helpful to encourage us to do better. ?About Sound Quality? Sound is sometimes personal and subjective. Different people have different favor and auditory sense. Some prefer high, some enjoy mid or bass. Moreover, the output sound also differs from different audio files. We always try to provide as rich as possible sound for you. For lack of bass, please try to adjust the ear tips, or change to smaller ear tips and push them a little deeper inside your ears to see if you could get better effect. ?About Noise Isolation? The headphones are ergonomically oblique angle designed for your comfortable wearing experience and better noise isolation.