diff --git a/Model/Resolver/Stock.php b/Model/Resolver/Stock.php
index 61209f1..60901bf 100755
--- a/Model/Resolver/Stock.php
+++ b/Model/Resolver/Stock.php
@@ -17,15 +17,11 @@
 class Stock implements ResolverInterface
 {
     public function __construct(
-        \Magento\Catalog\Api\ProductRepositoryInterface $productRepository,
-        \Magento\Customer\Model\Customer $customer,
-        \Magento\Store\Model\StoreManagerInterface $storeManager,
-        \Magento\ProductAlert\Model\Stock $stock
+        protected \Magento\Catalog\Api\ProductRepositoryInterface $_productRepository,
+        protected \Magento\Customer\Model\Customer $_customer,
+        protected \Magento\Store\Model\StoreManagerInterface $_storeManager,
+        protected \Magento\ProductAlert\Model\Stock $_stock
     ) {
-        $this->_productRepository = $productRepository;
-        $this->_customer = $customer;
-        $this->_storeManager = $storeManager;
-        $this->_stock = $stock;
     }
 
     public function resolve(Field $field, $context, ResolveInfo $info, array $value = null, array $args = null)