Stylish Portable MP3 Music Speaker with FM Radio/SD Slot/USB Host/Multi-Color LED - Black

Mine came with a BL-5C battery, 3.7V 800mAh.
Battery size approx ~2.09"x ~1.35" x ~0.22" (53.05x33.84x5.62mm).
So far sku.22691 is the highest capacity battery for this device, that should give you the longest battery life.
Sounds better when you place it in a corner or on a table against a wall.
I did some basic testing, and the little cube plays well from 100Hz to just about as high as my ears and hardware go; although the boost in 2,5kHz colors the high frequencies of the cymbals a bit.
I tried removing the LED, but I would not recommend it. Although it's pretty easy to remove the plastic plate (4 screws), I presume the cube is glued together, so no opening.
The best thing you can do if the LED annoys you, is get a black permanent marker, remove the transparent foot, and color the LED black, and the part on the transparent foot plate where it shines in.
It should reduce the LED light quite a bit!
You can always remove the permanent marker with some rubbing alcohol.
Or, use some black paper and insert it between the light and the foot.
I don't know if I ever am going to use the LED light, but it's included!
It sounds the loudest around 2.5kHz and 1kHz.
I heard people say it has between 24 and 48 hours of battery life on radio, and between 8 and 10 of MP3. I will have to see this first, and will put my findings in the comment section.