diff --git a/Source/Modified Teensy Libraries/output_mqs.cpp b/Source/Modified Teensy Libraries/output_mqs.cpp
index ee88aec..26f1857 100644
--- a/Source/Modified Teensy Libraries/output_mqs.cpp	
+++ b/Source/Modified Teensy Libraries/output_mqs.cpp	
@@ -25,6 +25,8 @@
  */
 // Frank B
 
+// modified for use with SIDKick!
+
 #if defined(__IMXRT1052__) || defined(__IMXRT1062__)
 #include <Arduino.h>
 #include "output_mqs.h"
diff --git a/Source/Modified Teensy Libraries/output_mqs.h b/Source/Modified Teensy Libraries/output_mqs.h
index 7d5359d..0ab4401 100644
--- a/Source/Modified Teensy Libraries/output_mqs.h	
+++ b/Source/Modified Teensy Libraries/output_mqs.h	
@@ -24,6 +24,8 @@
  * THE SOFTWARE.
  */
 
+// modified for use with SIDKick!
+
 #if defined(__IMXRT1052__) || defined(__IMXRT1062__)
 #ifndef output_mqs_h_
 #define output_mqs_h_
diff --git a/Source/Modified Teensy Libraries/output_pt8211.cpp b/Source/Modified Teensy Libraries/output_pt8211.cpp
index d3a2fc7..98bbdf1 100644
--- a/Source/Modified Teensy Libraries/output_pt8211.cpp	
+++ b/Source/Modified Teensy Libraries/output_pt8211.cpp	
@@ -26,6 +26,7 @@
 
 //Adapted to PT8211, Frank Bösing, Ben-Rheinland
 
+// modified for use with SIDKick!
 
 #include <Arduino.h>
 #include "output_pt8211.h"
diff --git a/Source/Modified Teensy Libraries/output_pt8211.h b/Source/Modified Teensy Libraries/output_pt8211.h
index 9aac701..ff1a8f7 100644
--- a/Source/Modified Teensy Libraries/output_pt8211.h	
+++ b/Source/Modified Teensy Libraries/output_pt8211.h	
@@ -26,6 +26,8 @@
 
 //Adapted to PT8211, Frank Bösing.
 
+// modified for use with SIDKick!
+
 #ifndef output_pt8211_h_
 #define output_pt8211_h_
 
diff --git a/Source/Modified Teensy Libraries/readme.txt b/Source/Modified Teensy Libraries/readme.txt
new file mode 100644
index 0000000..bdfff36
--- /dev/null
+++ b/Source/Modified Teensy Libraries/readme.txt	
@@ -0,0 +1 @@
+These files are originally of the Teensy audio library and have been modified for use with SIDKick.