diff --git a/configtool/board.py b/configtool/board.py
index de16ba2..6a5e4a8 100644
--- a/configtool/board.py
+++ b/configtool/board.py
@@ -99,7 +99,7 @@ class Board:
         helpKey = None
 
         self.cfgValues = {}
-        self.cfgNames = []
+        self.cfgNames = set()
         self.helpText = {}
 
         prevLines = ""
@@ -230,7 +230,7 @@ class Board:
         if m:
             t = m.groups()
             if len(t) == 1:
-                self.cfgNames.append(t[0])
+                self.cfgNames.add(t[0])
             return True
 
         return False
diff --git a/configtool/printer.py b/configtool/printer.py
index 9b35e26..cd6ea0f 100644
--- a/configtool/printer.py
+++ b/configtool/printer.py
@@ -56,7 +56,7 @@ class Printer:
         helpKey = None
 
         self.cfgValues = {}
-        self.cfgNames = []
+        self.cfgNames = set()
         self.helpText = {}
 
         prevLines = ""
@@ -145,7 +145,7 @@ class Printer:
         if m:
             t = m.groups()
             if len(t) == 1:
-                self.cfgNames.append(t[0])
+                self.cfgNames.add(t[0])
             return True
 
         return False