diff --git a/SabreTools.Models/TAR/Archive.cs b/SabreTools.Models/TAR/Archive.cs
index 47a425e..c167179 100644
--- a/SabreTools.Models/TAR/Archive.cs
+++ b/SabreTools.Models/TAR/Archive.cs
@@ -7,6 +7,6 @@ namespace SabreTools.Models.TAR
         /// <summary>
         /// 1 or more entries
         /// </summary>
-        public List<Entry>? Entries { get; set; }
+        public Entry[]? Entries { get; set; }
     }
 }
\ No newline at end of file
diff --git a/SabreTools.Models/TAR/Block.cs b/SabreTools.Models/TAR/Block.cs
index c3a3481..0c98ec5 100644
--- a/SabreTools.Models/TAR/Block.cs
+++ b/SabreTools.Models/TAR/Block.cs
@@ -2,6 +2,6 @@ namespace SabreTools.Models.TAR
 {
     public sealed class Block
     {
-        public readonly byte[] Data = new byte[512];
+        public byte[]? Data = new byte[512];
     }
 }
\ No newline at end of file
diff --git a/SabreTools.Models/TAR/Header.cs b/SabreTools.Models/TAR/Header.cs
index b4edfe8..6bc18d5 100644
--- a/SabreTools.Models/TAR/Header.cs
+++ b/SabreTools.Models/TAR/Header.cs
@@ -17,42 +17,42 @@ namespace SabreTools.Models.TAR
         /// </summary>
         /// <remarks>Octal string representation</remarks>
         [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 8)]
-        public byte[]? Mode;
+        public string? Mode;
 
         /// <summary>
         /// Owner's numeric user ID
         /// </summary>
         /// <remarks>Octal string representation</remarks>
         [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 8)]
-        public byte[]? UID;
+        public string? UID;
 
         /// <summary>
         /// Owner's numeric group ID
         /// </summary>
         /// <remarks>Octal string representation</remarks>
         [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 8)]
-        public byte[]? GID;
+        public string? GID;
 
         /// <summary>
         /// File size in bytes
         /// </summary>
         /// <remarks>Octal string representation</remarks>
         [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 12)]
-        public byte[]? Size;
+        public string? Size;
 
         /// <summary>
         /// Last modification time in numeric Unix time format
         /// </summary>
         /// <remarks>Octal string representation</remarks>
         [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 12)]
-        public byte[]? ModifiedTime;
+        public string? ModifiedTime;
 
         /// <summary>
         /// Checksum for header record
         /// </summary>
         /// <remarks>Octal string representation</remarks>
         [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 8)]
-        public byte[]? Checksum;
+        public string? Checksum;
 
         /// <summary>
         /// Link indicator (file type) / Type flag