The Wenger Flashlight tool is a small incandescent flashlight that is fitted into the layers of a couple of specialised Swiss Army Knives known as the Spot Light Series. The light is activated by a momentary push-button switch located on the back of the knife (the corkscrew side). The flashlight is powered by two AAAA batteries, and the bulb is user-replaceable. The life of the power source is rated at 100 activations at 30 seconds each.
The overall design such as housing, mounting, switching, and power-source are closely related to that of the Wenger Laser Pointer Tool.
Instruction leaflet here.
See also: LED Light - A white light layer tool in some Victorinox models.