diff --git a/src/main/java/jssc/SerialNativeInterface.java b/src/main/java/jssc/SerialNativeInterface.java
index 86f627624..ebc5f20a1 100644
--- a/src/main/java/jssc/SerialNativeInterface.java
+++ b/src/main/java/jssc/SerialNativeInterface.java
@@ -339,7 +339,7 @@ public static String getLibraryVersion() {
      * Send Break signal for set duration
      * 
      * @param handle handle of opened port
-     * @param duration duration of Break signal
+     * @param duration duration of Break signal, in milliseconds
      * @return If the operation is successfully completed, the method returns true, otherwise false
      *
      * @since 0.8
diff --git a/src/main/java/jssc/SerialPort.java b/src/main/java/jssc/SerialPort.java
index 14f9acc9e..c2ded5307 100644
--- a/src/main/java/jssc/SerialPort.java
+++ b/src/main/java/jssc/SerialPort.java
@@ -922,7 +922,7 @@ public int getFlowControlMode() throws SerialPortException {
     /**
      * Send Break singnal for set duration
      *
-     * @param duration duration of Break signal
+     * @param duration duration of Break signal, in milliseconds
      *
      * @return If the operation is successfully completed, the method returns true, otherwise false
      *