1. Outdoor mode - Maximum sound and maximum distance (applicable to outdoor duty and outdoor shooting range)2. Indoor mode - normal hearing and distance (applicable to indoor shooting range)3. Mute mode - listening to Bluetooth audio or making phone calls (applicable to listening to music or making phone calls)When the Bluetooth function of m20t is turned on, the sound pickup and noise reduction also work synchronously. Through the intelligent (acoustic optimization tracking algorithm and acoustic design exclusive to actor technology, it can accurately identify environmental noise and human voice. At the same time, configure the whistling suppression controller to suppress echo and whistling. The combination of the two brings a clearer call and listening experience.Actually, when you are in a noisy shooting range or busy subway market, you can take it calmly in the face of a sudden call or wechat voice. You don't have to rush to find a quiet place around. All the other party can hear is the voice you want to convey.Wearing for a long time, comfort is also very important. The single side weight of the headset is only 8.3g, which is light and does not drop the ear. The earphone box is very small and weighs only 72g. It's not heavy in your pocket. There's no need to worry about portability.It also supports ipx5 splash proof. It doesn't matter in case of light rain or sweat.The battery life is also reliable. The battery life of the headset can reach 8 hours when it is fully charged.