10Pcs MQ-7 MQ7 CO Carbon Monoxide Gas Sensor Module For Arduino Specification: Detection range: 10 to 1000ppmm Characteristic gas: 100ppmm CO Sensitive resistance: 2K!#!amp!*!Omega; to 20K!#!amp!*!Omega; in 100ppm CO Sensitivity: !#!amp!*!ge; 3% Response time: !#!amp!*!le; 1s Recovery time: !#!amp!*!le; 30s Heating resistance: 31!#!amp!*!Omega; !#!amp!*!plusmn; 3!#!amp!*!Omega; Heating current: !#!amp!*!le; 180mA Heating voltage: 5.0V!#!amp!*!plusmn;0.2V \/ 1.5!#!amp!*!plusmn;0.1V Heating power: about 350mW Size: 3.5 x 2.2cm (1.4 x 0.9inch) Standard operating conditions: Ambient Temperature: -20 C to +50 C Humidity: !#!amp!*!le; 95%RH Oxygen Content: 21% Note: Mainly used for CO， gas detection in family， factory or underground operation. Package included: 10 x MQ-7 CO gas sensor module