diff --git a/libraries/AP_Motors/AP_MotorsMulticopter.cpp b/libraries/AP_Motors/AP_MotorsMulticopter.cpp
index defe70cde4..fbc96e9a3a 100644
--- a/libraries/AP_Motors/AP_MotorsMulticopter.cpp
+++ b/libraries/AP_Motors/AP_MotorsMulticopter.cpp
@@ -104,14 +104,14 @@ const AP_Param::GroupInfo AP_MotorsMulticopter::var_info[] = {
 
     // @Param: SPIN_MIN
     // @DisplayName: Motor Spin minimum
-    // @Description: Point at which the thrust starts expressed as a number from 0 to 1 in the entire output range
+    // @Description: Point at which the thrust starts expressed as a number from 0 to 1 in the entire output range.  Should be higher than MOT_SPIN_ARM.
     // @Values: 0.0:Low, 0.15:Default, 0.3:High
     // @User: Advanced
     AP_GROUPINFO("SPIN_MIN", 18, AP_MotorsMulticopter, _spin_min, AP_MOTORS_SPIN_MIN_DEFAULT),
 
     // @Param: SPIN_ARM
     // @DisplayName: Motor Spin armed
-    // @Description: Point at which the motors start to spin expressed as a number from 0 to 1 in the entire output range
+    // @Description: Point at which the motors start to spin expressed as a number from 0 to 1 in the entire output range.  Should be lower than MOT_SPIN_MIN.
     // @Values: 0.0:Low, 0.1:Default, 0.2:High
     // @User: Advanced
     AP_GROUPINFO("SPIN_ARM", 19, AP_MotorsMulticopter, _spin_arm, AP_MOTORS_SPIN_ARM_DEFAULT),