The MICS-4514 is a compact MOS sensor with two fully independent sensing elements on one package, designed for robust detection of pollution from automobile exhausts. It features a smallest footprint of 5 × 7 × 1.55 mm with one RED sensor element for detecting reducing gases (CO, H2, NH3, CH4) and one OX sensor element for detecting oxidizing gases (NO2), each with independent heaters and sensitive layers. The RED sensor has a sensing resistance range of 100–1500 kO in air and detects CO at 1–1000 ppm, while the OX sensor has a sensing resistance range of 0.8–20 kO and detects NO2 at 0.05–10 ppm. Operating from a 4.9–5.1 V supply with heating power of 76 mW (RED) and 43 mW (OX), the sensor is robust for harsh environments and suitable for high-volume manufacturing in automotive emission monitoring, air quality systems, and industrial gas detection applications.