There are two primary sensor types: Fuel Cell Sensors and Semiconductor Sensors. Fuel cell sensors offer high precision, long-term stability, and are alcohol-specific, making them the gold standard for law enforcement and professional medical use. Semiconductor sensors are more affordable and compact, suitable for personal or promotional use, but they can be sensitive to 'false positives' from substances like cigarette smoke or mouthwash. For B2B buyers, fuel cell technology is recommended for high-end retail or professional distribution due to its superior accuracy.