5100 Zoom IR Illuminator

from http://www.nightvisionstore.com

Increase the viewing ability of your night vision device with the Rigel 5100 IR Illuminator. Made for the Rigel 4200 night vision rifle scope and fits on many other night vision devices. The Rigel 5100 IR produces an infrared Illumination [akin to a flashlight] making objects visible in pitch-black conditions when natural light sources are absent. The Rigel IR Illuminator features a standard tripod-size mounting bolt for easy installment on most rifle scopes.

see:
http://www.nightvisionstore.com/Rigel%205100%20Zoom%20IR%20Illuminator.htm