diff --git a/libraries/AP_RangeFinder/AP_RangeFinder_Params.cpp b/libraries/AP_RangeFinder/AP_RangeFinder_Params.cpp
index 879dc6cf8d..f093e86779 100644
--- a/libraries/AP_RangeFinder/AP_RangeFinder_Params.cpp
+++ b/libraries/AP_RangeFinder/AP_RangeFinder_Params.cpp
@@ -12,7 +12,7 @@ const AP_Param::GroupInfo AP_RangeFinder_Params::var_info[] = {
 
     // @Param: PIN
     // @DisplayName: Rangefinder pin
-    // @Description: Analog or PWM input pin that rangefinder is connected to.  Airspeed ports can be used for Analog input, AUXOUT can be used for PWM input
+    // @Description: Analog or PWM input pin that rangefinder is connected to. Airspeed ports can be used for Analog input, AUXOUT can be used for PWM input. When using analog pin 103, the maximum value of the input in 3.3V.
     // @Values: -1:Not Used,11:Pixracer,13:Pixhawk ADC4,14:Pixhawk ADC3,15:Pixhawk ADC6/Pixhawk2 ADC,50:AUX1,51:AUX2,52:AUX3,53:AUX4,54:AUX5,55:AUX6,103:Pixhawk SBUS
     // @User: Standard
     AP_GROUPINFO("PIN",     2, AP_RangeFinder_Params, pin, -1),