COB light

Chip-on-board packs many tiny LED dies onto one substrate so they behave as a single bright point of light. That concentration is what makes the output usable with modifiers, since a softbox or a parabolic reflector needs a small source to shape. Run bare, a COB is harsh and unflattering. Most take a Bowens mount, which opens up a large accessory market, and the bigger ones need a fan you can hear on a quiet dialogue recording. Panels spread their LEDs over a wide surface instead and give softer light straight out of the box with far less control over where it goes.