diff --git a/libraries/AP_Compass/Compass.cpp b/libraries/AP_Compass/Compass.cpp
index 86e6beb061..f48a0b0362 100644
--- a/libraries/AP_Compass/Compass.cpp
+++ b/libraries/AP_Compass/Compass.cpp
@@ -153,7 +153,7 @@ const AP_Param::GroupInfo Compass::var_info[] PROGMEM = {
     // @Param: PRIMARY
     // @DisplayName: Choose primary compass
     // @Description: If more than one compass is available this selects which compass is the primary. Normally 0=External, 1=Internal. If no External compass is attached this parameter is ignored
-    // @Values: 0:FirstCompass,1:SecondCompass
+    // @Values: 0:FirstCompass,1:SecondCompass,2:ThirdCompass
     // @User: Advanced
     AP_GROUPINFO("PRIMARY", 12, Compass, _primary, 0),
 #endif