After all 7 screws are removed, we can easily crack this thing open. And voila! We can clearly see 4 speakers and the mainboard. The sides of the case has some kind of foam to make sure air moving inside the case can't easily escape to provide maximum vibration to the passive radiator.

4 tiny speakers

One of the two passive radiator

3.7 Wh Lithium Ion Battery. Rated for 8 hours of continous usage by Boomphones

If we assume the battery Voltage is 3.7 V, it means the battery has a 1000mAh capacity.

Battery connector

MicroUSB charging & audio input connector

Speaker connector