diff --git a/Elwig/Models/DeliveryPart.cs b/Elwig/Models/DeliveryPart.cs
index af5d0b1..a4ddd6c 100644
--- a/Elwig/Models/DeliveryPart.cs
+++ b/Elwig/Models/DeliveryPart.cs
@@ -54,10 +54,10 @@ namespace Elwig.Models {
         public virtual WineOrigin Origin { get; private set; }
 
         [Column("kgnr")]
-        public int KgNr { get; set; }
+        public int? KgNr { get; set; }
 
         [ForeignKey("KgNr")]
-        public virtual WbKg Kg { get; private set; }
+        public virtual WbKg? Kg { get; private set; }
 
         [Column("rdnr")]
         public int? RdNr { get; set; }