Tynny-13FD video light

Small enough to sit on an action camera or a phone housing without turning it into a rig: 13.2 cm (5.2 in) long and 100 g (3.5 oz) in the water, so it barely changes how the camera hangs. The number that matters here is CRI 96. Color rendering is how faithfully a light shows the colors it falls on, and cheap lights in the 70s and low 80s turn the reds of an anthias or a soft coral muddy brown, which no editing fully brings back. 2200 lumens across 110 degrees is close-range light, for a nudibranch or a moray at arm's length, not for a whole wall. Runs an hour on full and charges over USB-C, so it lives off the same cable as everything else in the bag.