diff --git a/SabreTools.Core/Filter/FilterObject.cs b/SabreTools.Core/Filter/FilterObject.cs
index e0ae74a0..2b96c4df 100644
--- a/SabreTools.Core/Filter/FilterObject.cs
+++ b/SabreTools.Core/Filter/FilterObject.cs
@@ -12,9 +12,14 @@ namespace SabreTools.Core.Filter
     public class FilterObject
     {
         /// <summary>
-        /// Key name for the filter
+        /// Item name associated with the field
         /// </summary>
-        public readonly string[] Key;
+        public readonly string ItemName;
+
+        /// <summary>
+        /// Field name associated with the filter
+        /// </summary>
+        public readonly string FieldName;
 
         /// <summary>
         /// Value to match in the filter
@@ -31,30 +36,33 @@ namespace SabreTools.Core.Filter
             if (!SplitFilterString(filterString, out var keyItem, out Operation operation, out var value))
                 throw new ArgumentOutOfRangeException(nameof(filterString));
 
-            if (!FilterParser.ParseFilterId(keyItem, out var itemName, out var fieldName))
+            if (!FilterParser.ParseFilterId(keyItem, out string itemName, out string fieldName))
                 throw new ArgumentOutOfRangeException(nameof(filterString));
 
-            Key = [itemName, fieldName];
+            ItemName = itemName;
+            FieldName = fieldName;
             Value = value;
             Operation = operation;
         }
 
         public FilterObject(string itemField, string? value, string? operation)
         {
-            if (!FilterParser.ParseFilterId(itemField, out var itemName, out var fieldName))
+            if (!FilterParser.ParseFilterId(itemField, out string itemName, out string fieldName))
                 throw new ArgumentOutOfRangeException(nameof(value));
 
-            Key = [itemName, fieldName];
+            ItemName = itemName;
+            FieldName = fieldName;
             Value = value;
             Operation = GetOperation(operation);
         }
 
         public FilterObject(string itemField, string? value, Operation operation)
         {
-            if (!FilterParser.ParseFilterId(itemField, out var itemName, out var fieldName))
+            if (!FilterParser.ParseFilterId(itemField, out string itemName, out string fieldName))
                 throw new ArgumentOutOfRangeException(nameof(value));
 
-            Key = [itemName!, fieldName!];
+            ItemName = itemName;
+            FieldName = fieldName;
             Value = value;
             Operation = operation;
         }
@@ -66,7 +74,7 @@ namespace SabreTools.Core.Filter
         /// </summary>
         public bool Matches(DictionaryBase dictionaryBase)
         {
-            // TODO: Add validation of dictionary base type from Key[0]
+            // TODO: Add validation of dictionary base type from the key values
             return Operation switch
             {
                 Operation.Equals => MatchesEqual(dictionaryBase),
@@ -85,11 +93,11 @@ namespace SabreTools.Core.Filter
         private bool MatchesEqual(DictionaryBase dictionaryBase)
         {
             // If the key doesn't exist, we count it as null
-            if (!dictionaryBase.ContainsKey(Key[1]))
+            if (!dictionaryBase.ContainsKey(FieldName))
                 return Value == null;
 
             // If the value in the dictionary is null
-            string? checkValue = dictionaryBase.ReadString(Key[1]);
+            string? checkValue = dictionaryBase.ReadString(FieldName);
             if (checkValue == null)
                 return Value == null;
 
@@ -128,11 +136,11 @@ namespace SabreTools.Core.Filter
         private bool MatchesNotEqual(DictionaryBase dictionaryBase)
         {
             // If the key doesn't exist, we count it as null
-            if (!dictionaryBase.ContainsKey(Key[1]))
+            if (!dictionaryBase.ContainsKey(FieldName))
                 return Value != null;
 
             // If the value in the dictionary is null
-            string? checkValue = dictionaryBase.ReadString(Key[1]);
+            string? checkValue = dictionaryBase.ReadString(FieldName);
             if (checkValue == null)
                 return Value == null;
 
@@ -171,11 +179,11 @@ namespace SabreTools.Core.Filter
         private bool MatchesGreaterThan(DictionaryBase dictionaryBase)
         {
             // If the key doesn't exist, we count it as null
-            if (!dictionaryBase.ContainsKey(Key[1]))
+            if (!dictionaryBase.ContainsKey(FieldName))
                 return false;
 
             // If the value in the dictionary is null
-            string? checkValue = dictionaryBase.ReadString(Key[1]);
+            string? checkValue = dictionaryBase.ReadString(FieldName);
             if (checkValue == null)
                 return false;
 
@@ -204,11 +212,11 @@ namespace SabreTools.Core.Filter
         private bool MatchesGreaterThanOrEqual(DictionaryBase dictionaryBase)
         {
             // If the key doesn't exist, we count it as null
-            if (!dictionaryBase.ContainsKey(Key[1]))
+            if (!dictionaryBase.ContainsKey(FieldName))
                 return false;
 
             // If the value in the dictionary is null
-            string? checkValue = dictionaryBase.ReadString(Key[1]);
+            string? checkValue = dictionaryBase.ReadString(FieldName);
             if (checkValue == null)
                 return false;
 
@@ -237,11 +245,11 @@ namespace SabreTools.Core.Filter
         private bool MatchesLessThan(DictionaryBase dictionaryBase)
         {
             // If the key doesn't exist, we count it as null
-            if (!dictionaryBase.ContainsKey(Key[1]))
+            if (!dictionaryBase.ContainsKey(FieldName))
                 return false;
 
             // If the value in the dictionary is null
-            string? checkValue = dictionaryBase.ReadString(Key[1]);
+            string? checkValue = dictionaryBase.ReadString(FieldName);
             if (checkValue == null)
                 return false;
 
@@ -270,11 +278,11 @@ namespace SabreTools.Core.Filter
         private bool MatchesLessThanOrEqual(DictionaryBase dictionaryBase)
         {
             // If the key doesn't exist, we count it as null
-            if (!dictionaryBase.ContainsKey(Key[1]))
+            if (!dictionaryBase.ContainsKey(FieldName))
                 return false;
 
             // If the value in the dictionary is null
-            string? checkValue = dictionaryBase.ReadString(Key[1]);
+            string? checkValue = dictionaryBase.ReadString(FieldName);
             if (checkValue == null)
                 return false;
 
diff --git a/SabreTools.Core/Filter/FilterRunner.cs b/SabreTools.Core/Filter/FilterRunner.cs
index 32e19503..0430fb90 100644
--- a/SabreTools.Core/Filter/FilterRunner.cs
+++ b/SabreTools.Core/Filter/FilterRunner.cs
@@ -54,9 +54,9 @@ namespace SabreTools.Core.Filter
             foreach (var filter in Filters)
             {
                 // If the filter isn't for this object type, skip
-                if (filter.Key[0] != itemName)
+                if (filter.ItemName != itemName)
                     continue;
-                else if (filter.Key[0] == "item" && Array.IndexOf(TypeHelper.GetDatItemTypeNames(), itemName) > -1)
+                else if (filter.ItemName == "item" && Array.IndexOf(TypeHelper.GetDatItemTypeNames(), itemName) > -1)
                     continue;
 
                 // If we don't get a match, it's a failure
diff --git a/SabreTools.DatItems/DatItem.cs b/SabreTools.DatItems/DatItem.cs
index 0313e105..a5a86035 100644
--- a/SabreTools.DatItems/DatItem.cs
+++ b/SabreTools.DatItems/DatItem.cs
@@ -145,10 +145,12 @@ namespace SabreTools.DatItems
                 FileTypes.Archives.TapeArchive => new Rom(baseFile),
                 FileTypes.Archives.XZArchive => new Rom(baseFile),
                 FileTypes.Archives.ZipArchive => new Rom(baseFile),
+                FileTypes.BaseArchive => new Rom(baseFile),
+                FileTypes.Folder => null, // Folders cannot be a DatItem
+                FileTypes.BaseFile => new Rom(baseFile),
 
                 // Miscellaneous
-                null => null,
-                _ => new Rom(baseFile),
+                _ => null,
             };
         }
 
diff --git a/SabreTools.Test/Filter/PopulationTests.cs b/SabreTools.Test/Filter/PopulationTests.cs
index 7a79cf5b..e54c6256 100644
--- a/SabreTools.Test/Filter/PopulationTests.cs
+++ b/SabreTools.Test/Filter/PopulationTests.cs
@@ -43,11 +43,13 @@ namespace SabreTools.Test.Filter
             var filter = new FilterRunner(filters);
 
             // Check the filters
-            Assert.Equal(new string[] {"machine", "name"}, filter.Filters[0].Key);
+            Assert.Equal("machine", filter.Filters[0].ItemName);
+            Assert.Equal("name", filter.Filters[0].FieldName);
             Assert.Equal("foo", filter.Filters[0].Value);
             Assert.Equal(Operation.Equals, filter.Filters[0].Operation);
 
-            Assert.Equal(new string[] {"machine", "name"}, filter.Filters[1].Key);
+            Assert.Equal("machine", filter.Filters[1].ItemName);
+            Assert.Equal("name", filter.Filters[1].FieldName);
             Assert.Equal("bar", filter.Filters[1].Value);
             Assert.Equal(Operation.NotEquals, filter.Filters[1].Operation);
         }
@@ -66,11 +68,13 @@ namespace SabreTools.Test.Filter
             var filter = new FilterRunner(filters);
 
             // Check the filters
-            Assert.Equal(new string[] { "rom", "name"}, filter.Filters[0].Key);
+            Assert.Equal("rom", filter.Filters[0].ItemName);
+            Assert.Equal("name", filter.Filters[0].FieldName);
             Assert.Equal("foo", filter.Filters[0].Value);
             Assert.Equal(Operation.Equals, filter.Filters[0].Operation);
 
-            Assert.Equal(new string[] { "item", "name"}, filter.Filters[1].Key);
+            Assert.Equal("item", filter.Filters[1].ItemName);
+            Assert.Equal("name", filter.Filters[1].FieldName);
             Assert.Equal("bar", filter.Filters[1].Value);
             Assert.Equal(Operation.NotEquals, filter.Filters[1].Operation);
         }
diff --git a/SabreTools.Test/Filtering/CleaningTests.cs b/SabreTools.Test/Filtering/CleaningTests.cs
index 2e7a5f33..f8afcd0d 100644
--- a/SabreTools.Test/Filtering/CleaningTests.cs
+++ b/SabreTools.Test/Filtering/CleaningTests.cs
@@ -67,7 +67,7 @@ namespace SabreTools.Test.Filtering
             // Check the fields
             Assert.Equal("name", datItem.GetName());
             Assert.Equal("!", datItem.GetFieldValue<Machine>(DatItem.MachineKey)!.GetStringFieldValue(Models.Metadata.Machine.NameKey));
-            Assert.Equal("name-3", datItem.GetFieldValue<Machine>(DatItem.MachineKey)!.GetStringFieldValue(Models.Metadata.Machine.DescriptionKey));
+            Assert.Equal("!", datItem.GetFieldValue<Machine>(DatItem.MachineKey)!.GetStringFieldValue(Models.Metadata.Machine.DescriptionKey));
         }
 
         [Theory]