The vibration of the UPRIGHT GO 2 is designed to be gentle yet noticeable. It is there to notify you when you slouch without interrupting your daily routine.
If you feel the vibration, but it is not noticeable enough for you, try changing the following in your app under Settings -> Vibration:
Vibration Pattern: Short, Medium, Long, Knock Knock, Ramp-Up, and more. Choose one that is best for you.
Vibration Strength: Gentle, Medium, Strong. Here you may want to choose strong if your vibration is too gentle.
The most important thing to remember is that you feel comfortable while using your UPRIGHT GO 2.
Lastly, you can place your device a little higher on your spine, or slightly to the side of your spine. Most people feel the vibration better when it's positioned higher on the back.
If this doesn't help, please let us know. You may contact us at firstname.lastname@example.org or via our in-app or web chat.