diff --git a/js/concentration-api-routes.js b/js/concentration-api-routes.js
index 28b527d..fff6f0c 100644
--- a/js/concentration-api-routes.js
+++ b/js/concentration-api-routes.js
@@ -22,6 +22,14 @@ define( function( require ) {
     'concentrationScreen.concentrationMeterProbe': 'concentrationScreen.view.concentrationMeterNode.probeNode',
 
     // TODO: Could be confusing here to refer to the button of the combobox as the combo box
-    'concentrationScreen.soluteComboBox': 'concentrationScreen.view.soluteControls.soluteComboBox.buttonNode' 
+    'concentrationScreen.soluteComboBox': 'concentrationScreen.view.soluteControls.soluteComboBox.buttonNode',
+    'concentrationScreen.soluteComboBox.drinkMixButton': 'concentrationScreen.view.soluteControls.soluteComboBox.itemNodeList.drinkMix',
+    'concentrationScreen.soluteComboBox.cobaltIINitrate': 'concentrationScreen.view.soluteControls.soluteComboBox.itemNodeList.cobaltIINitrate',
+    'concentrationScreen.soluteComboBox.cobaltChloride': 'concentrationScreen.view.soluteControls.soluteComboBox.itemNodeList.cobaltChloride',
+    'concentrationScreen.soluteComboBox.potassiumDichromate': 'concentrationScreen.view.soluteControls.soluteComboBox.itemNodeList.potassiumDichromate',
+    'concentrationScreen.soluteComboBox.potassiumChromate': 'concentrationScreen.view.soluteControls.soluteComboBox.itemNodeList.potassiumChromate',
+    'concentrationScreen.soluteComboBox.nickelIIChloride': 'concentrationScreen.view.soluteControls.soluteComboBox.itemNodeList.nickelIIChloride',
+    'concentrationScreen.soluteComboBox.copperSulfate': 'concentrationScreen.view.soluteControls.soluteComboBox.itemNodeList.copperSulfate',
+    'concentrationScreen.soluteComboBox.potassiumPermanganate': 'concentrationScreen.view.soluteControls.soluteComboBox.itemNodeList.potassiumPermanganate',
   };
 } );
diff --git a/js/concentration-api.js b/js/concentration-api.js
index 611b564..ceee7d0 100644
--- a/js/concentration-api.js
+++ b/js/concentration-api.js
@@ -55,6 +55,11 @@ define( function( require ) {
     parent: Node // not exactly a button, see implementation
   };
 
+  var ComboBoxButton = {
+    name: 'ComboBoxButton',
+    parent: Node // Also a special case
+  };
+
   // Use explicit names for id keys so they will match what researchers see in data files
   // Use id and type instead of componentID and typeID to simplify things for researchers
   // Use a map so that JS will help us check that there are no duplicate names.
@@ -91,6 +96,16 @@ define( function( require ) {
     },
     'concentrationScreen.soluteComboBox': {
       type: ComboBox
-    }
+    },
+    'concentrationScreen.soluteComboBox.drinkMixButton': {
+      type: ComboBoxButton
+    },
+    'concentrationScreen.soluteComboBox.cobaltIINitrate': { type: ComboBoxButton },
+    'concentrationScreen.soluteComboBox.cobaltChloride': { type: ComboBoxButton },
+    'concentrationScreen.soluteComboBox.potassiumDichromate': { type: ComboBoxButton },
+    'concentrationScreen.soluteComboBox.potassiumChromate': { type: ComboBoxButton },
+    'concentrationScreen.soluteComboBox.nickelIIChloride': { type: ComboBoxButton },
+    'concentrationScreen.soluteComboBox.copperSulfate': { type: ComboBoxButton },
+    'concentrationScreen.soluteComboBox.potassiumPermanganate': { type: ComboBoxButton }
   };
 } );
\ No newline at end of file