diff --git a/Docs/Dev/img/er.png b/Docs/Dev/img/er.png
new file mode 100644
index 0000000..cf2979b
Binary files /dev/null and b/Docs/Dev/img/er.png differ
diff --git a/Models/AttributeValueType.php b/Models/AttributeValueType.php
index df2d3a3..7dfc076 100755
--- a/Models/AttributeValueType.php
+++ b/Models/AttributeValueType.php
@@ -26,11 +26,11 @@ use phpOMS\Stdlib\Base\Enum;
  */
 abstract class AttributeValueType extends Enum
 {
-    public const _INT = 0;
+    public const _INT = 1;
 
-    public const _STRING = 1;
+    public const _STRING = 2;
 
-    public const _FLOAT = 2;
+    public const _FLOAT = 3;
 
-    public const _DATETIME = 3;
+    public const _DATETIME = 4;
 }
diff --git a/Models/Item.php b/Models/Item.php
index 0ada2f2..f7d339c 100755
--- a/Models/Item.php
+++ b/Models/Item.php
@@ -200,7 +200,33 @@ class Item
     }
 
     /**
-     * Add doc to item
+     * Add attribute to item
+     *
+     * @param ItemAttribute $attribute Note
+     *
+     * @return void
+     *
+     * @since 1.0.0
+     */
+    public function addAttribute(ItemAttribute $attribute) : void
+    {
+        $this->attributes[] = $attribute;
+    }
+
+    /**
+     * Get attributes
+     *
+     * @return ItemAttribute[]
+     *
+     * @since 1.0.0
+     */
+    public function getAttributes() : array
+    {
+        return $this->attributes;
+    }
+
+    /**
+     * Add note to item
      *
      * @param EditorDoc $note Note
      *