This info from https://manualzz.com/doc/54512487/boltune-bt-bh001-earbud-headphone-user-guide
| 1 | + | Volume + / Next |
| 2 | Δ | Multifunction |
| 3 | LED indicator / Microphone | |
| 4 | - | Volume - / Previous |
Connect with USB adapter. Fully charged when indicator turns blue.
If earphones cannot pair with your Bluetooth device, press and hold the Multifunction Δ button when earphones are off for 10 seconds until LED indicator flashes purple twice (reset to factory settings). This clears pairing history. Then follow instructions above.
| Power On | Press and hold Multifunction Δ for 1 second |
| Power Off | Press and hold Multifunction Δ for 3 seconds |
| Enter pairing mode | Press and hold Multifunction Δ for 5 seconds |
| Play/Pause | Press Multifunction Δ once |
| Volume + / - | press + / - button |
| Next/Previous track | Press and hold +/- button |
| Answer or hang up phone | Press Multifunction Δ once |
| Decline incoming call | Press Multifunction Δ for 1 second |
| Redial last call | Press Multifunction Δ twice |
| Reset to factory settings | When earphones off, press and hold Multifunction Δ for 10 seconds, until LED indicator flashes purple twice. |