diff --git a/Grid/qcd/action/momentum/MomentumFilter.h b/Grid/qcd/action/momentum/MomentumFilter.h
index 2a15d80c..0a84b7e2 100644
--- a/Grid/qcd/action/momentum/MomentumFilter.h
+++ b/Grid/qcd/action/momentum/MomentumFilter.h
@@ -28,8 +28,7 @@ directory
 *************************************************************************************/
 /*  END LEGAL */
 //--------------------------------------------------------------------
-#ifndef MOMENTUM_FILTER
-#define MOMENTUM_FILTER
+#pragma once 
 
 NAMESPACE_BEGIN(Grid);
 
@@ -90,5 +89,3 @@ struct MomentumFilterApplyPhase: public MomentumFilterBase<MomentaField>{
 
 
 NAMESPACE_END(Grid);
-
-#endif