diff --git a/Influx/AllaganTools/Inventory.cs b/Influx/AllaganTools/Inventory.cs
index 3a4ff80..449e353 100644
--- a/Influx/AllaganTools/Inventory.cs
+++ b/Influx/AllaganTools/Inventory.cs
@@ -23,7 +23,8 @@ internal sealed class Inventory
     public IEnumerable<InventoryItem> GetAllItems() =>
         ((IEnumerable)_getAllInventories.Invoke(_delegate, Array.Empty<object>())!)
         .Cast<IEnumerable>()
-        .SelectMany(x => x.Cast<object>())
-        .Select(x => new InventoryItem(x))
+        .SelectMany(x => x.Cast<object?>())
+        .Where(x => x != null)
+        .Select(x => new InventoryItem(x!))
         .ToList();
 }
diff --git a/Influx/SubmarineTracker/SubmarineStats.cs b/Influx/SubmarineTracker/SubmarineStats.cs
index 36186c6..9230e6c 100644
--- a/Influx/SubmarineTracker/SubmarineStats.cs
+++ b/Influx/SubmarineTracker/SubmarineStats.cs
@@ -1,8 +1,8 @@
 namespace Influx.SubmarineTracker;
 
-public class SubmarineStats
+public sealed class SubmarineStats
 {
-    public string Name { get; init; }
-    public int Id { get; init; }
-    public ushort Level { get; init; }
+    public required string Name { get; init; }
+    public required int Id { get; init; }
+    public required ushort Level { get; init; }
 }