CORE 1250 Lumen Rechargeable Lantern with Bluetooth Speaker - Model 40078

CORE do not publish a range figure for this model, so we are not going to quote one. In practice a standard Bluetooth speaker holds a connection across a normal campsite; expect it to drop if you walk off with your phone.

Both run off the same two 18650 cells, so yes - playing music will shorten the runtimes quoted for the light alone. The 19 hours on low assumes the speaker is off.

Take this one if you want music and more peak brightness. Take the 750 if you want endurance: it runs 86 hours on low against 19 here, and costs less. They are aimed at different trips.

Yes, there is a USB output port. It is a useful backup, though every mAh you put into a phone is light and music you do not get later.

It is ANSI rated for a 1 metre drop, which covers knocking it off a camp table. It is not a rugged work light.

IPX4 handles rain and splashes. Do not submerge it.

Spare lithium cells and power banks must travel in your cabin bag and are not allowed in checked luggage - that is a firm rule on every airline out of Julius Nyerere, not a preference. Protect the terminals so nothing can short against keys or coins: keep the cell in its case, in the original packaging, or tape the contacts. A cell installed in the light itself may go either way, though the cabin is still the safer choice. Capacity limits only bite above 100 Wh, and a 21700 or 18650 cell is nowhere near that - roughly 13 to 18 Wh - so no airline approval is needed.