diff --git a/ArcFormats/Emic/ArcPACK.cs b/ArcFormats/Emic/ArcPACK.cs
index 4e3f37ee..8542b50a 100644
--- a/ArcFormats/Emic/ArcPACK.cs
+++ b/ArcFormats/Emic/ArcPACK.cs
@@ -51,6 +51,11 @@ namespace GameRes.Formats.Emic
         public override bool  IsHierarchic { get { return true; } }
         public override bool     CanCreate { get { return false; } }
 
+        public PacOpener ()
+        {
+            Extensions = new string[] { "pac" };
+        }
+
         public override ArcFile TryOpen (ArcView file)
         {
             int count = file.View.ReadInt32 (0x28);