Self diagnosis function with built-in Microprocessor Detection gas from low to high concentration owing to various detection principle Easy installation with a wall mount type Check it from a distance by large display and flashing light 4-digit gas concentration display 3-stage alarm level, 1-trouble LED display and relay contact output  Easy configuration of  monitoring by RS-485 Modbus communication Programmable alarm setting (Level, Time delay) Self diagnosis 4-20mA(Current source or Sink) output signal