This single gas detector is specifically designed for toxic or flammable gas detection. It is featured by fast response, high sensitivity and equipped with rechargeable lithium battery. Its shell adopts engineering plastic combined with composite coating technique, providing comfortable hand feel and not easy falling from hands. Special water-proof and anti-oxidation treatment is made to the sensor, buzzer and charging port to make shell more resistant. The whole device is designed with easy carry body, reliable quality, and leading low power consumption technology.