The flashlight tail cap is a way to lighten the end of your flashlight. The FTC operates in two modes: flash and constant on. It is perfect to use as a signal, to read a map, and to conserve energy in low light situations. Initiated from the FTC, but emits a different color Flash mode as signal Flood light as candle Embed low light level and extend 50 times longer of runtime Fits all equal size flashlights of other brands driven at 3-9 volts For NEXTORCH model # T6A, T9, Z6, Z9