Diffusion transmitter for combustible gas detection with an explosion-proof aluminium housing. Supports 4–20 mA current-source or current-sink output and includes an FND display for inspection and calibration. One-person calibration simplifies maintenance. Catalytic, hot-wire semiconductor and thermal-conductivity sensor options cover different combustible gas ranges. Suitable for wall or 2-inch pole mounting; operating temperature: −20°C to 60°C.