diff --git a/reactos/hal/halx86/include/bus.h b/reactos/hal/halx86/include/bus.h
index 9175f5eef8f..2ca1cbf2ed4 100644
--- a/reactos/hal/halx86/include/bus.h
+++ b/reactos/hal/halx86/include/bus.h
@@ -135,7 +135,7 @@ typedef struct _PCI_REGISTRY_INFO_INTERNAL
 {
     UCHAR MajorRevision;
     UCHAR MinorRevision;
-    UCHAR NoBuses;
+    UCHAR NoBuses; // Number Of Buses
     UCHAR HardwareMechanism;
     ULONG ElementCount;
     PCI_CARD_DESCRIPTOR CardList[ANYSIZE_ARRAY];
diff --git a/reactos/ntoskrnl/include/internal/pci.h b/reactos/ntoskrnl/include/internal/pci.h
index 3dae7d63fc1..135895f0a8a 100644
--- a/reactos/ntoskrnl/include/internal/pci.h
+++ b/reactos/ntoskrnl/include/internal/pci.h
@@ -86,7 +86,7 @@ typedef struct _PCI_REGISTRY_INFO
 {
     UCHAR MajorRevision;
     UCHAR MinorRevision;
-    UCHAR NoBuses;
+    UCHAR NoBuses; // Number Of Buses
     UCHAR HardwareMechanism;
 } PCI_REGISTRY_INFO, *PPCI_REGISTRY_INFO;