The back plate has four lateral walls and a bottom plate. A back side of the bottom plate includes multiple sets of folding hooks. Each set corresponds a different installation platform. One of the multiple sets of folding hooks is folded to be used for hooking to a corresponding installation platform. The light source module has multiple LED modules disposed on the bottom plate. Each LED module has a LED device and a lens. The lens diffuses a light of the LED device to be evenly emitted from the lens and broadening an output angle of the light via the lens. The diffusion plate with a peripheral edge is fixed to the four lateral walls of the back plate. The driver cover is attached to an external side of one of the four walls of the back plate. The driver cover defines a container cavity for concealing the driver module.