The Pebbles use vibrations to guide your breathing exercises. It is normal for these vibration mechanisms to produce a small noise during their operation. If the sound is too loud or distracting, this may indicate a problem.

Here are some steps to fix and fix the issue:

1. Battery level: A low battery can sometimes cause devices to behave unexpectedly. Fully charge your Pebbles and see if the sound lasts.
2. Restart the session: Put your Pebbles into sleep mode and then wake them up to reset them. By performing a reset, minor problems and glitches can often be resolved.
3. Make sure you use it correctly: Make sure you use the Pebbles as intended. Abuse or improper handling may cause unusual noises.
4. Check for loose parts: Shake the Pebbles gently and listen for any rattles or movements inside, which may indicate a loose part. If applicable, seek professional help from the Glimp support team. Please don't try to open or disassemble the Pebbles yourself, as this will void the warranty and may cause further damage.

If the sound persists, contact Glimp Customer Service for further assistance. We can provide more in-depth troubleshooting or advice on next steps, possibly including a warranty claim if necessary.