diff --git a/src/loadSimu.hpp b/src/loadSimu.hpp
new file mode 100644
index 0000000..1215a88
--- /dev/null
+++ b/src/loadSimu.hpp
@@ -0,0 +1,40 @@
+#ifndef __COSMOTOOLBOX_HPP
+#define __COSMOTOOLBOX_HPP
+
+
+namespace CosmoTool
+{
+  static const int NEED_GADGET_ID = 1;
+  static const int NEED_POSITION = 2;
+  static const int NEED_VELOCITY = 4;
+  
+
+  class SimuData 
+  {
+  public:
+    float BoxSize;
+    float time;
+
+    long NumPart;
+    int *Id;
+    float *Pos[3];
+    float *Vel[3];
+  public:
+    SimuData() : Id(0),NumPart(0)  { Pos[0]=Pos[1]=Pos[2]=0; Vel[0]=Vel[1]=Vel[2]=0; }
+    ~SimuData() 
+    {
+      for (int j = 0; j < 3; j++)
+	{
+	  if (Pos[j])
+	    delete[] Pos[j];
+	  if (Vel[j])
+	    delete[] Vel[j];
+	}
+      if (Id)
+	delete[] Id;
+    }    
+  };
+
+};
+
+#endif