The invention provides a device (10) for identifying a person or an object. The device (10) includes a transparent body (42), and embedded within the transparent body (42), a printed circuit board (PCB) (46), a plurality of light emitting diodes (LEDs) (48) electrically connected to the PCB (46), and a diffuser (16). The diffuser (16) is arranged to diffuse light emitted from the LEDs (48) thereby to illuminate the transparent body (42) to form a light source for identifying a person or an object attached to the device (10).