diff --git a/AudioMultiply_F32.h b/AudioMultiply_F32.h
index 55988ec..aeaf284 100644
--- a/AudioMultiply_F32.h
+++ b/AudioMultiply_F32.h
@@ -1,5 +1,5 @@
 /*
- * AudioEffectsGain
+ * AudioMultiply
  * 
  * Created: Patrick Radius, December 2016
  * Purpose: Multiply two channels of audio data. Can be used for example as 'vca' or amplitude modulation.
@@ -9,6 +9,8 @@
  *          
  * MIT License.  use at your own risk.
 */
+#ifndef AUDIOMULTIPLYF32_H
+#define AUDIOMULTIPLYF32_H
 
 #include <arm_math.h>
 #include <AudioStream_F32.h>
@@ -22,3 +24,5 @@ class AudioMultiply_F32 : public AudioStream_F32
   private:
     audio_block_f32_t *inputQueueArray_f32[2];
 };
+
+#endif