diff --git a/src/Services/EntityMergers/Mergers/EntityMergerInterface.php b/src/Services/EntityMergers/Mergers/EntityMergerInterface.php
index 9c8d9eb9..838bc1d6 100644
--- a/src/Services/EntityMergers/Mergers/EntityMergerInterface.php
+++ b/src/Services/EntityMergers/Mergers/EntityMergerInterface.php
@@ -24,12 +24,17 @@ declare(strict_types=1);
 namespace App\Services\EntityMergers\Mergers;
 
 
+/**
+ * @template T of object
+ */
 interface EntityMergerInterface
 {
     /**
      * Determines if this merger supports merging the other entity into the target entity.
      * @param  object  $target
+     * @phpstan-param T $target
      * @param  object  $other
+     * @phpstan-param T $other
      * @param  array  $context
      * @return bool True if this merger supports merging the other entity into the target entity, false otherwise
      */
@@ -39,8 +44,11 @@ interface EntityMergerInterface
      * Merge the other entity into the target entity.
      * The target entity will be modified and returned.
      * @param  object  $target
+     * @phpstan-param T $target
      * @param  object  $other
+     * @phpstan-param T $other
      * @param  array  $context
+     * @phpstan-return T
      * @return object
      */
     public function merge(object $target, object $other, array $context = []): object;
diff --git a/src/Services/EntityMergers/Mergers/PartMerger.php b/src/Services/EntityMergers/Mergers/PartMerger.php
index 6c839414..731da0b7 100644
--- a/src/Services/EntityMergers/Mergers/PartMerger.php
+++ b/src/Services/EntityMergers/Mergers/PartMerger.php
@@ -31,6 +31,9 @@ use App\Entity\Parts\PartLot;
 use App\Entity\PriceInformations\Orderdetail;
 use Symfony\Component\DependencyInjection\Attribute\Autoconfigure;
 
+/**
+ * @implements EntityMergerInterface<Part>
+ */
 #[Autoconfigure(public: true)]
 class PartMerger implements EntityMergerInterface
 {
@@ -74,7 +77,7 @@ class PartMerger implements EntityMergerInterface
         $this->mergeTags($target, $other, 'tags');
 
         //Merge manufacturing status
-        $this->useCallback(function (?ManufacturingStatus $t, ?ManufacturingStatus $o): ?ManufacturingStatus {
+        $this->useCallback(function (?ManufacturingStatus $t, ?ManufacturingStatus $o): ManufacturingStatus {
             //Use the other value, if the target value is not set
             if ($t === ManufacturingStatus::NOT_SET || $t === null) {
                 return $o ?? ManufacturingStatus::NOT_SET;
@@ -91,6 +94,9 @@ class PartMerger implements EntityMergerInterface
             return $t;
         }, $target, $other, 'providerReference');
 
+        //Merge the collections
+        $this->mergeCollectionFields($target, $other, $context);
+
         return $target;
     }