Abstract: A hand-held illuminating device for finding a blood vessel (e.g., vein) for blood transfusion includes a main body adapted to be stably held by the hand; and a battery powered illumination assembly in the main body and comprising a circuit board, a plurality of LEDs mounted on the circuit board and electrically connected thereto, a dim switch on an outer surface of the main body for activating the LEDs or not, and a lens on one end of the main body in proximity to the LEDs. The LEDs comprises a plurality of red LEDs capable of emitting red light having a wavelength in the range of 590 mm to 660 mm, and a plurality of orange LEDs capable of emitting orange light having a wavelength in the range of 590 mm to 660 mm.