This is Withings Activité Pop Smartwatch. A beautifully designed no frills smartwatch that shows your daily activity score with an analogue gauge. Remove the rubber band by pulling tiny levers at the back along arrow direction.

The case back can be opened by prying with the opening tool or a flat screwdriver. You will see the CR2025 lithium battery shining with all its glory.

Pry the CR2025 lithium battery off and ponder the meaning of three hexadecimal numbers on the information sticker.

Using a thin flat blade screwdriver remove three self tapping screws holding the inner plastic cover. The vibration motor (round metal part in second photo) has a sticky tape on it. You may need to apply force to separate the motor from the inner plastic cover. See the main PCB.

Using a thin flat blade screwdriver remove 12 (!) fine threaded screws to release the main PCB from the stepper motors of three dial hands.

...and enjoy the view.

...and enjoy the view.

This Withings Activité Pop Smartwatch had water ingress and it failed due to corrosion. A common fault with this watch is loose inner screws, leading to poor PCB contact with motors. When you change battery make sure you apply silicone grease on the rubber gasket of the case back. The dial and hands are not accessible since the glass is pressed.