The photoacoustic sensing technology has several advantages over the conventional NDIR (non-dispersive infrared) sensor technology. Same as typical NDIR sensors, the PASens® technology realizes high sensitivity and accuracy. However, in contrast to typical NDIR sensors, the SCD4x bypasses the tradeoff between miniaturization and performance. Further, the SCD4x avoids manual through-hole soldering thanks to its compatibility with standard SMT processes. All sensor elements are protected by the metal-cap, resulting in high robustness against dust, condensation, and mechanical impact.