Abstract: A wafer battery has a light-emitting diode attached to its jacket, with one ead of the diode soldered to the battery jacket, and the other lead extending around the battery and overhanging its anode. The combination of diode and battery is encapsulated in a cover of elastomeric material, with a pressure-sensitive adhesive on one side. The bezel is applied to crystal of an instrument such as a meter, gauge, or the like and illuminates the gauge when a series connection is completed between the battery and light-emitting diode by pressing the cover over the battery anode to make the light-emitting diode lead contact the anode. The bezel is small with respect to the surface area of the crystal to which it is applied, in order that is not obscure the scale, dial, or face of the instrument. An alternate embodiment has one lead of the light-emitting diode soldered to the battery anode and the other lead extending over the side of the battery jacket.