The APF (Advanced Pulse-Frequency Transmission System) was developed by Fenix laboratory, a major technology breakthrough of flashlight industry. Allowing the tactical flashlight achieve a higher level of performance:

• Take light to the extreme. Traditional forward switches are limited by current, and it is difficult to achieve brightness above 2000 lumens. In the age of 21700 batteries gradually expanding, 3100 lumens tactical flashlights are almost impossible; while the flashlight using APF technology can.
• Make the functional tail cap simpler. Traditional multi-function tail cap needs to achieve functional through the double-layer body or additional channels ; and the flashlight using APF technology offering a strong reliable flashlight in simple structure, we talking about single layer body if specifically.