diff --git a/metrics.h b/metrics.h
index 4eac003..2a84b98 100644
--- a/metrics.h
+++ b/metrics.h
@@ -514,6 +514,15 @@
   static const int kMetricWifiAvailableBSSesMin;
   static const int kMetricWifiAvailableBSSesNumBuckets;
 
+  // Reason that the mac80211 TX queue is stopped.
+  static const char kMetricWifiStoppedTxQueueReason[];
+
+  // Maximal queue length amongst all stopped mac80211 TX queues.
+  static const char kMetricWifiStoppedTxQueueLength[];
+  static const int kMetricWifiStoppedTxQueueLengthMax;
+  static const int kMetricWifiStoppedTxQueueLengthMin;
+  static const int kMetricWifiStoppedTxQueueLengthNumBuckets;
+
   // Number of services associated with currently connected network.
   static const char kMetricServicesOnSameNetwork[];
   static const int kMetricServicesOnSameNetworkMax;