diff --git a/plot_single_transmission.py b/plot_single_transmission.py
index e2157c0..9411879 100755
--- a/plot_single_transmission.py
+++ b/plot_single_transmission.py
@@ -147,7 +147,7 @@ if __name__ == "__main__":
         ax00.set_ylim(0, 16)
         ax01.set_ylim(0, 21)
 
-        ax00.set_xlabel("arrival time")
+        ax00.set_xlabel("arrival time [s]")
         ax2.set_ylabel("Goodput [mbps]")
         ax00.set_ylabel("CQI")
         ax1.set_ylabel("sRTT [s]")