I was able to get at the electronics by bending the strap and prying the hard plastic enclosure out with a sharp utility razor.

Note the 4 metal pads where the USB interface connects - we'll come back to those.

The Vivosmart is waterproof rated up to 5 ATM so accessing the electronics is not easy. Keep prying and picking away and it will come out eventually.

The electronics will eventually come out in one enclosed package and you'll be left with a flexible strap with a translucent insert.

Note the feel of the strap - Garmin possibly used a soft TPS rather than the stickier feeling silicone rubber commonly used in other wearable devices.