diff --git a/docs/main.md b/docs/main.md
index 6f10f06..fff1b00 100644
--- a/docs/main.md
+++ b/docs/main.md
@@ -4,7 +4,7 @@ Documentation
 **Aspect**
 
 * [About](./about.md)
-* [Requirements and installation](./install.md)
+* [Install](./install.md)
 * [Syntax](./syntax.md)
 * [Settings](./settings.md)
 * [Callbacks and filters](./callbacks.md)
@@ -12,23 +12,22 @@ Documentation
 
 **Modifiers**
 
-Conversation about [modifiers](./syntax.md#modifiers)
-
 * [upper](./mods/upper.md) aka `up`
 * [lower](./mods/lower.md) aka `low`
 * [date_format](./mods/date_format.md)
 * [date](./mods/date.md)
 * [truncate](./mods/truncate.md)
-* [escape](./mods/escape.md) aka `e`, `url`
+* [escape](./mods/escape.md) aka `e`
 * [unescape](./mods/unescape.md)
 * [strip](./mods/strip.md)
 * [length](./mods/lenght.md)
+* [in](./mods/in.md)
 * allowed functions: `json_encode`, `json_decode`, `count`, `is_string`, `is_array`, `is_numeric`, `is_int`, `is_object`,
 `strtotime`, `gettype`, `is_double`, `ip2long`, `long2ip`, `strip_tags`, `nl2br`
 
-**Tags**
+[Using](./syntax.md#modifiers) and [addition](./ext/mods.md) of modifiers.
 
-Conversation about [tags](./syntax.md#tags)
+**Tags**
 
 * [var](./tags/var.md)
 * [if](./tags/if.md), `elseif` and `else`
@@ -44,6 +43,8 @@ Conversation about [tags](./syntax.md#tags)
 * [macro](./tags/macro.md)
 * [import](./tags/import.md)
 
+[Using](./syntax.md#tags) and [addition](./ext/tags.md) of tags.
+
 **Extends**
 
 * [Add tags](./ext/tags.md)
diff --git a/docs/mods/in.md b/docs/mods/in.md
new file mode 100644
index 0000000..68db2ce
--- /dev/null
+++ b/docs/mods/in.md
@@ -0,0 +1,8 @@
+Modifier |in
+============
+
+```smarty
+{if $number|in:[1, 3, 55]}
+...
+{/if}
+```
\ No newline at end of file
diff --git a/src/Aspect/Modifier.php b/src/Aspect/Modifier.php
index 0d16c3c..2a73fda 100644
--- a/src/Aspect/Modifier.php
+++ b/src/Aspect/Modifier.php
@@ -129,4 +129,17 @@ class Modifier {
             return count((array)$item);
         }
     }
+
+    /**
+     *
+     * @param $value
+     * @param $list
+     * @return bool
+     */
+    public static function in($value, $list) {
+        if(is_array($list)) {
+            return in_array($value, $list);
+        }
+        return false;
+    }
 }