1. Strong voice--safety warning Even in the harsh enviroment,it also can keep loud sound,continuous beep up to 1 minute.. 2. Long life and reliable quality A.high-quality sonorant diaphragm B.adopt membrane filter technology with waterproof and propulsive gas C.unique adherent point protection craftwork D.anti-weather material...

1. Strong voice--safety warning Even in the harsh enviroment,it also can keep loud sound,continuous beep up to 1 minute.. 2. Long life and reliable quality A.high-quality sonorant diaphragm B.adopt membrane filter technology with waterproof and propulsive gas C.unique adherent point protection craftwork D.Anti-weather material...