diff --git a/src/main/java/org/apache/commons/lang3/Range.java b/src/main/java/org/apache/commons/lang3/Range.java
index ce129d4a5..0a5dd7f83 100644
--- a/src/main/java/org/apache/commons/lang3/Range.java
+++ b/src/main/java/org/apache/commons/lang3/Range.java
@@ -21,6 +21,8 @@
 
 /**
  * <p><code>Range</code> represents an immutable range of numbers of the same type.</p>
+ * <p>The objects need to either be implementations of <code>java.lang.Comparable</code>
+ * or you need to supply a <code>java.util.Comparator</code>. </p>
  * 
  * <p>#ThreadSafe#</p>
  * @author Apache Software Foundation