ITEM NAME:MQ2 Smoke Gas Detection Alarm Sensor Switch Module for Arduino DIY Projects Description: This Smoke/LPG/CO Gas Sensor(MQ2) module utilizes an MQ-2 as the sensitive component and has a protection resistor and an adjustable resistor on board The MQ-2 gas sensor is sensitive to LPG, i-butane, propane, methane, alcohol, Hydrogen and smoke It could be used in gas leakage detecting equipments in family and industry The resistance of the sensitive component changes as the concentration of the target gas changes Made of premium quality material, durable and practical Specification: Overall Dimension: 50mm x 18mm / 2 x 0.7 Inch Input Voltage: 5V DC Result: Digital DO: 0.1V / 5V [TTL Switch] with DO LED display; Analog AO: 0.1 to 0.3 V [ Higher Value Means Higher pollution ] Package Includes: 1 Piece Gas Sensor Module SKU: DMO0013405860012801.This Smoke/LPG/CO Gas Sensor(MQ2) module utilizes an MQ-2 as the sensitive component and has a protection resistor and an adjustable resistor on board. 1 Piece Gas Sensor Module. The resistance of the sensitive component changes as the concentration of the target gas changes.