diff --git a/src/wireviz/Harness.py b/src/wireviz/Harness.py
index f1f3b43..cbab7b5 100644
--- a/src/wireviz/Harness.py
+++ b/src/wireviz/Harness.py
@@ -125,8 +125,8 @@ class Harness:
 
             rows = [[remove_links(connector.name) if connector.show_name else None],
                     [f'P/N: {remove_links(connector.pn)}' if connector.pn else None,
-                     html_line_breaks(pn_info_string("mpn", connector.manufacturer, connector.mpn)),
-                     html_line_breaks(pn_info_string("spn", connector.supplier, connector.spn))],
+                     html_line_breaks(pn_info_string(HDR_MPN, connector.manufacturer, connector.mpn)),
+                     html_line_breaks(pn_info_string(HDR_SPN, connector.supplier, connector.spn))],
                     [html_line_breaks(connector.type),
                      html_line_breaks(connector.subtype),
                      f'{connector.pincount}-pin' if connector.show_pincount else None,
@@ -209,10 +209,10 @@ class Harness:
 
             rows = [[remove_links(cable.name) if cable.show_name else None],
                     [f'P/N: {remove_links(cable.pn)}' if (cable.pn and not isinstance(cable.pn, list)) else None,
-                     html_line_breaks(pn_info_string("mpn",
+                     html_line_breaks(pn_info_string(HDR_MPN,
                         cable.manufacturer if not isinstance(cable.manufacturer, list) else None,
                         cable.mpn if not isinstance(cable.mpn, list) else None)),
-                     html_line_breaks(pn_info_string("spn",
+                     html_line_breaks(pn_info_string(HDR_SPN,
                         cable.supplier if not isinstance(cable.supplier, list) else None,
                         cable.spn if not isinstance(cable.spn, list) else None))],
                     [html_line_breaks(cable.type),
@@ -267,10 +267,10 @@ class Harness:
                     wireidentification = []
                     if isinstance(cable.pn, list):
                         wireidentification.append(f'P/N: {remove_links(cable.pn[i - 1])}')
-                    manufacturer_info = pn_info_string("mpn",
+                    manufacturer_info = pn_info_string(HDR_MPN,
                         cable.manufacturer[i - 1] if isinstance(cable.manufacturer, list) else None,
                         cable.mpn[i - 1] if isinstance(cable.mpn, list) else None)
-                    supplier_info = pn_info_string("spn",
+                    supplier_info = pn_info_string(HDR_SPN,
                         cable.supplier[i - 1] if isinstance(cable.supplier, list) else None,
                         cable.spn[i - 1] if isinstance(cable.spn, list) else None)
                     if manufacturer_info:
diff --git a/src/wireviz/wv_bom.py b/src/wireviz/wv_bom.py
index cc17c45..e203145 100644
--- a/src/wireviz/wv_bom.py
+++ b/src/wireviz/wv_bom.py
@@ -144,8 +144,8 @@ def bom_list(bom: List[BOMEntry]) -> List[List[str]]:
     # Headers not specified here are generated by capitilising the internal name.
     bom_headings = {
         "pn": "P/N",
-        "mpn": "MPN",
-        "spn": "SPN"
+        "mpn": HDR_MPN,
+        "spn": HDR_SPN,
     }
     return ([[bom_headings.get(k, k.capitalize()) for k in keys]] +  # Create header row with key names
             [[make_str(entry.get(k)) for k in keys] for entry in bom])  # Create string list for each entry row
@@ -161,9 +161,11 @@ def component_table_entry(
         spn: Optional[str] = None,
     ) -> str:
     """Return a diagram node table row string with an additional component."""
-    manufacturer_str = pn_info_string("mpn", manufacturer, mpn)
-    supplier_str = pn_info_string("spn", supplier, spn)
-    part_number_list = [pn, manufacturer_str, supplier_str]
+    part_number_list = [
+        pn,
+        pn_info_string(HDR_MPN, manufacturer, mpn),
+        pn_info_string(HDR_SPN, supplier, spn),
+    ]
     output = (f'{qty}'
               + (f' {unit}' if unit else '')
               + f' x {type}'