dadly I would say it is waterproof, particularly on the solar panel side. However, the bulb side (with switches) is not quite so, since the on-off switch, as well as the plastic cover on that side, has no rubber seal. In any case, the bulb side normally faces down when you use it, and that should prevent rain water from seeping in.

dadly The whole lamp measues about 8 cm. wide, and 22.5 cm. long (top of lamp to bracket). The bulb area measures about 6 cm. X 9 cm.

dadly After removing 6 screws and lifting the front cover off, you can see a blue 18650 sized battery. I can only judge by the size, since there is no labelling on the battery. The connecting wires are soldered on the terminals. Since there is no labelling on the battery, the capacity is unknown.

dadly I bought the large one. It has 3 lithium 18650 batteries connected in parallel.

dadly Yes. You can pry open the lens cover using a small thin screw driver, then uncrew the 4 small screws of the led light panel, and you'll find three 18650 lithium batteries (for the large model) connected in parallel. However, they are welded together, but still replaceable.

dadly It is relatively more quiet than those older 12V pumps I used before.