A rock-solid example of smart, stealth-messaging technology, as seen in use by operatives in the Czech Signal Corp. Red, green and yellow lenses slide over a clear bulb to produce different hues, used to send clear communications silently across great distances. On the trail, this Flashlight can be used for reading maps, signs, logbooks and more. Switch from a constant beam to a flashing strobe for emergency signaling. Clip it to your belt when not in use. Very functional, not to mention a fascinating collectible and conversation piece.