A lighting device includes a first heat sink having a first surface and a second surface opposite the first surface, a second heat sink having a third surface and a fourth surface opposite the third surface. The third surface of the second heat sink is bonded to the second surface of the first heat sink. The lighting device further includes a plurality of first light emitting diode (LED) modules mounted on the first surface of the first heat sink; and a plurality of second light emitting diode (LED) modules mounted on the fourth surface of the second heat sink. One or more the first LED modules generally radiates lights in a first direction. One or more the second LED modules generally radiates lights in a second direction. The first and second LED modules are covered by respective non-reflective caps. The first LED module and the second LED module are configured to be selectively turned on or off according to a predefined algorithm. The first LED modules are arranged on an outer region of the lighting device, and the second LED modules are arranged on an inner region of the lighting device. The inner region is circumferentially surrounded by the outer region.