diff --git a/SabreTools.Metadata.DatItems/DatItem.cs b/SabreTools.Metadata.DatItems/DatItem.cs
index ac3834f9..88092f15 100644
--- a/SabreTools.Metadata.DatItems/DatItem.cs
+++ b/SabreTools.Metadata.DatItems/DatItem.cs
@@ -64,6 +64,12 @@ namespace SabreTools.Metadata.DatItems
         /// </summary>
         public Machine? Machine { get; set; }
 
+        /// <summary>
+        /// Machine index for a DatItem
+        /// </summary>
+        /// <remarks>0-indexed, a value less than 0 is considered invalid</remarks>
+        public long MachineIndex { get; set; } = -1;
+
         /// <summary>
         /// Flag if item should be removed
         /// </summary>
@@ -74,6 +80,12 @@ namespace SabreTools.Metadata.DatItems
         /// </summary>
         public Source? Source { get; set; }
 
+        /// <summary>
+        /// Source index for a DatItem
+        /// </summary>
+        /// <remarks>0-indexed, a value less than 0 is considered invalid</remarks>
+        public long SourceIndex { get; set; } = -1;
+
         #endregion
 
         #region Accessors