diff --git a/src/gas/README.txt b/src/gas/README.txt
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+Grove - Gas Sensor(MQ-2)：Combustible Gas、Smoke [middle sensitivity]
+Grove - Gas Sensor(MQ-3)：Alcohol and Benzine [HIGH sensitivity] Long warmup
+Grove - Gas Sensor(MQ-5)：LPG, Natural Gas, Town Gas [high sensitivity]
+Grove - Gas Sensor(MQ-9)：LPG, CO, CH4 [low sensitivity]
+
+Note - Gas sensor need to be heated, first minute the data is incorrect.