diff --git a/src/app/SDCardManager.cpp b/src/app/SDCardManager.cpp
index 8784fec..c84ced1 100644
--- a/src/app/SDCardManager.cpp
+++ b/src/app/SDCardManager.cpp
@@ -1,12 +1,12 @@
 #include "SDCardManager.h"
 
-SDCardManager::SDCardManager(SDClass& sdCard) : _sdCardRef(sdCard)
+SDCardManager::SDCardManager()
 {
 }
 
-double SDCardManager::getSize(const SizeUnit sizeUnit) const
+double SDCardManager::getSize(const SizeUnit sizeUnit)
 {
-  long numberOf512ByteChunks = _sdCardRef.cardSize();
+  long numberOf512ByteChunks = cardSize();
   long unit = 0;
   double result = 0;
   
@@ -37,8 +37,4 @@ double SDCardManager::getSize(const SizeUnit sizeUnit) const
   return result;
 }
 
-SDClass& SDCardManager::getSdCardHandler()
-{
-  return _sdCardRef;
-}
 
diff --git a/src/app/SDCardManager.h b/src/app/SDCardManager.h
index 7e75534..3f17d91 100644
--- a/src/app/SDCardManager.h
+++ b/src/app/SDCardManager.h
@@ -3,16 +3,14 @@
 #include <SD.h>
 #include "definition.h"
 
-class SDCardManager
+class SDCardManager : public SDClass
 {
   friend class SAB;
   public:
-  double getSize(const SizeUnit sizeUnit = GBYTE) const;
-  SDClass& getSdCardHandler();
+  double getSize(const SizeUnit sizeUnit = GBYTE);
   protected:
-    SDCardManager(SDClass& sdCard);
+    SDCardManager();
   private:
-    SDClass& _sdCardRef;
 };
 
 #endif //SDCARDMANAGER_H