The module contains a MQ-3 Gas Sensor and ETA1036. High sensitivity to alcohol and small sensitivity to benzine with a stable and long worklife are most important reasons to choose the MQ-3. The ETA1036 is a high efficiency synchronous step-up converter that can provide up to 3W of power to a boosted output from a low voltage source. The start-up voltage requires only 0.85v and the efficiency up to 96%. The MQ-3 is useful for alcohol detecting. There are different gas detectors for sale, like MQ2, MQ5 and MQ9. Below is a contrast table of them.