diff --git a/hardware/lascar-el-usb/protocol.c b/hardware/lascar-el-usb/protocol.c
index 508727ad..defbb5df 100644
--- a/hardware/lascar-el-usb/protocol.c
+++ b/hardware/lascar-el-usb/protocol.c
@@ -313,8 +313,8 @@ static void lascar_el_usb_dispatch(struct sr_dev_inst *sdi, unsigned char *buf,
 		packet.type = SR_DF_ANALOG;
 		packet.payload = &analog;
 		analog.num_samples = samples;
-		analog.mq = 0;
-		analog.unit = 0;
+		analog.mq = SR_MQ_CARBON_MONOXIDE;
+		analog.unit = SR_UNIT_CONCENTRATION;
 		analog.mqflags = 0;
 		if (!(analog.data = g_try_malloc(sizeof(float) * samples)))
 			break;
diff --git a/libsigrok.h b/libsigrok.h
index d68ec143..a1a50e42 100644
--- a/libsigrok.h
+++ b/libsigrok.h
@@ -176,6 +176,7 @@ enum {
 	/** Logarithmic representation of sound pressure relative to a
 	 * reference value. */
 	SR_MQ_SOUND_PRESSURE_LEVEL,
+	SR_MQ_CARBON_MONOXIDE,
 };
 
 /** Values for sr_datafeed_analog.unit. */
@@ -208,6 +209,7 @@ enum {
 	SR_UNIT_UNITLESS,
 	/** Sound pressure level relative so 20 micropascals. */
 	SR_UNIT_DECIBEL_SPL,
+	SR_UNIT_CONCENTRATION,
 };
 
 /** Values for sr_datafeed_analog.flags. */