diff --git a/sonoff/my_user_config.h b/sonoff/my_user_config.h
index 5b721af2a..825c6ad31 100644
--- a/sonoff/my_user_config.h
+++ b/sonoff/my_user_config.h
@@ -385,6 +385,8 @@
 
 #define USE_RC_SWITCH                            // Add support for RF transceiver using library RcSwitch (+2k7 code, 460 iram)
 
+//#define USE_MMHG                                 // Use mmHg instead of hPa
+
 /*********************************************************************************************\
  * Debug features are only supported in development branch
 \*********************************************************************************************/