The band Brian Dipert got on a Groupon 'mystery box' deal for $39.99. A white Skechers GOwalk activity monitor (shown here out of the box).
The charger looks like a lump of black plastic. There are two metal contacts on the band to connect to it.
The PCB-etched Bluetooth antenna is clearly visible. Underneath the PCB, at the bottom of the 'sandwich,' is the lithium polymer battery.
Again with flashbacks to an earlier Microsoft Band tear down, I thought I was going to have a struggle getting the module cracked open, especially since the backside label had alluded to 10m water resistance features. But it ended up not being bad at all. Grabbing the slotted screwdriver again, I used it as a crowbar at an end point where the white and frosted plastic edges met, and the two sides promptly popped apart.
Once the seam was split, further progress was accomplished with ease.
The LED is in the middle. The large IC on the right side has a black glop-top epoxy-obscured identity, unfortunately; I'm guessing it's the microcontroller-plus-memory.
The IC on the left is a Nordic Semiconductor nRF8001 Bluetooth Low Energy transceiver. Here's a view of it and its antenna.
The bottom side of the PCB is sticky-adhered to the battery underneath it. Peeling them apart wasn't at all difficult.
The adhesive unfortunately had mussed up the battery markings, but I think they say that it's 3.7V with a 30 mAH capacity rating.
Here's a closer look at the battery markings.
Here's the underside of the PCB that the battery powers.
In the lower right corner is the three-axis accelerometer. When I do a Google search on '263 8452,' the first result that comes up is a PDF datasheet for NXP's MMA8452Q, although I suspect that this particular flavour is made by some other manufacturer.
The ICs (and PCB containing them) are already faintly visible underneath the frosted plastic (and by the way, the shiny metal 'knob' on the left side in the second photo has no electrical purpose that I can discern; I think it's only there to help hold the module in place within the surrounding rubberized band).