diff --git a/src/Uom.php b/src/Uom.php
index f72ef83..e07ea98 100644
--- a/src/Uom.php
+++ b/src/Uom.php
@@ -17,8 +17,7 @@ public function __construct(
         $name,
         $description = '',
         $symbol = '',
-        $conversionFactor = '',
-        $quantity = ''
+        $conversionFactor = ''
     ) {
         if (empty($commonCode) || empty($name)) {
             throw new InvalidArgumentException('UoM requires common code and name');