diff --git a/src/USPSBase.php b/src/USPSBase.php
index 83653ba..517ea8f 100644
--- a/src/USPSBase.php
+++ b/src/USPSBase.php
@@ -431,7 +431,7 @@ public function getErrorMessage()
     protected function getValueByKey($array, $key)
     {
         foreach ($array as $k => $each) {
-            if ($k == $key) {
+            if ($k === $key) {
                 return $each;
             }