I bought this 3V LED bulb for an old lighted handheld magnifier. The size and radiation behavior of this LED lamp correspond to the dimensions of the old lamp (see photo). As expected, the power consumption of this LED lamp is well below that of a 2.5V light bulb (LED approx. 40mA, light bulb approx. 250mA). Also, the LED bulb still produced a decent amount of light when the battery voltage dropped to 2.75V (voltage reduced by the bulb).