The Fenix AER-01 switch (formerly AR-102) houses four sensors and a steel spring-switch module for consistent performance and reliability. The cable extends up to 80cm and the switch is triggered with slight finger pressure. Fitting lights that are 1" in diameter, the main circle switch functions just like the tail cap power switch, turning the light off and on, while the pressure pad serves as a "half-press" of the tail cap switch, achieving only momentary illumination. With the exception of the PD35TAC (only in Tactical Mode), the AER-01 cannot change brightness levels.