To remove the electronics from the hard plastic base we need to dig out a lot more sealant.

I first pried up the end of the PCB near the USB interface.

Finally (pic 2) the electrical assembly is free! Three rigid boards connected by flex.

Check out the antenna built into the flex circuitry - looks like a PIFA.

You can keep prying and release the

70mAh Li-ion battery

and buzzer.