diff --git a/app/Models/Item.php b/app/Models/Item.php
index 96863fa..c778b39 100644
--- a/app/Models/Item.php
+++ b/app/Models/Item.php
@@ -69,6 +69,11 @@ class Item extends Model
         return $this->hasMany(ClassCharacteristic::class, 'item_id', 'id');
     }
 
+    public function requestCharacteristics()
+    {
+        return $this->hasMany(RequestCharacteristic::class, 'item_id', 'id');
+    }
+
     public function weightValidations()
     {
         return $this->hasMany(WeightValidation::class);
diff --git a/app/Models/Machine.php b/app/Models/Machine.php
index a6e4e33..a342563 100644
--- a/app/Models/Machine.php
+++ b/app/Models/Machine.php
@@ -48,6 +48,11 @@ class Machine extends Model
         return $this->hasMany(ClassCharacteristic::class, 'machine_id', 'id');
     }
 
+    public function requestCharacteristics()
+    {
+        return $this->hasMany(RequestCharacteristic::class, 'machine_id', 'id');
+    }
+
     public function testingPanelReadings()
     {
         return $this->hasMany(TestingPanelReading::class);
diff --git a/app/Models/Plant.php b/app/Models/Plant.php
index 99dcb01..fe20e4a 100644
--- a/app/Models/Plant.php
+++ b/app/Models/Plant.php
@@ -128,6 +128,11 @@ class Plant extends Model
     //     return $this->hasMany(RejectReason::class, 'plant_id', 'id');
     // }
 
+    public function requestCharacteristics()
+    {
+        return $this->hasMany(RequestCharacteristic::class, 'plant_id', 'id');
+    }
+
     public function users()
     {
         return $this->hasMany(User::class, 'plant_id', 'id');