diff --git a/README.md b/README.md
index f48b358..d8d80a6 100644
--- a/README.md
+++ b/README.md
@@ -18,6 +18,9 @@ code complexity and enhancing performance.
   - [Saving `HasOne`, `MorphOne` relations](#saving-hasone-morphone-relations)
   - [Saving `HasMany`, `MorphMany` relations](#saving-hasmany-morphmany-relations)
   - [Saving `HasMany`, `MorphMany` relations with `sync` mode](#saving-hasmany-morphmany-relations-with-sync-mode)
+  - [Saving `BelongsToMany` relation](#saving-belongstomany-relation)
+  - [Saving `BelongsToMany` relation with `sync` mode](#saving-belongstomany-relation-with-sync-mode)
+  - [Response file](#response-file)
 - [FAQ](#faq)
 - [License](#license)
 - [Other packages](#other-packages)
@@ -167,6 +170,7 @@ $item->update([
 ]);
 ```
 
+
 ### Saving `HasMany`, `MorphMany`  relations
 You can **save** `HasMany`, `MorphMany` relations in the same way as a file. If relations exists, it will be updated, otherwise it will be created
 
@@ -210,6 +214,68 @@ $item->update([
 ```
 
 
+### Saving `BelongsToMany` relation
+
+```php
+$item = Item::query()->first();
+
+$item->update([
+    'categories' => [1, 2, 3] // belongsToMany relations
+]);
+
+$item->update([
+    'categories' => [ // belongsToMany relation
+        1 => ['name' => 'Category 1'], 
+        2 => ['name' => 'Category 2'], 
+        3 => ['name' => 'Category 3']
+    ]
+]);
+```
+
+
+### Saving `BelongsToMany` relation with `sync` mode
+You can **sync** the `BelongsToMany` relation. Everything that is not specified when saving will be deleted
+
+```php
+$item = Item::query()->first();
+
+$item->update([
+    'categories' => [ // belongsToMany relation
+        'mode' => 'sync', // not specified relations will be deleted
+        'value' => [1, 2, 3]
+    ]
+]);
+
+$item->update([
+    'categories' => [ // belongsToMany relation
+        'mode' => 'sync', // not specified relations will be deleted
+        'value' => [
+            1 => ['name' => 'Category 1'], 
+            2 => ['name' => 'Category 2'], 
+            3 => ['name' => 'Category 3']
+        ]
+    ]
+]);
+```
+
+
+### Response file
+Use the **responseFile** method to return a file in a controller
+
+```php
+class FileController extends Controller
+{
+
+    public function index()
+    {
+        $item = Item::query()->first();
+        return $item->responseFile('image');
+    }
+
+}
+```
+
+
 ## FAQ
 Check closed [issues](https://github.com/kolirt/laravel-master-model/issues) to get answers for most asked questions
 
diff --git a/composer.json b/composer.json
index 9153126..46dd312 100644
--- a/composer.json
+++ b/composer.json
@@ -14,7 +14,7 @@
     ],
     "homepage": "https://github.com/kolirt/laravel-master-model",
     "license": "MIT",
-    "version": "4.0.3",
+    "version": "4.0.4",
     "authors": [
         {
             "name": "kolirt"
diff --git a/src/Traits/MasterModel.php b/src/Traits/MasterModel.php
index 36da5eb..2720db9 100644
--- a/src/Traits/MasterModel.php
+++ b/src/Traits/MasterModel.php
@@ -94,6 +94,7 @@ public function fill(array $attributes)
                     case $relation instanceof \Illuminate\Database\Eloquent\Relations\MorphOne:
                     case $relation instanceof \Illuminate\Database\Eloquent\Relations\HasMany:
                     case $relation instanceof \Illuminate\Database\Eloquent\Relations\MorphMany:
+                    case $relation instanceof \Illuminate\Database\Eloquent\Relations\BelongsToMany:
                         $this->relations_to_save[] = [
                             'relation_name' => $key,
                             'relation' => $relation,
@@ -278,6 +279,21 @@ public function save(array $options = [])
                             $this->setRelation($relation_name, $loaded_relations);
                         }
 
+                        break;
+
+                    /**
+                     * Save BelongsToMany relation
+                     */
+                    case $relation instanceof \Illuminate\Database\Eloquent\Relations\BelongsToMany:
+                        $mode = $value['mode'] ?? null;
+                        $value = key_exists('value', $value) ? $value['value'] : $value;
+
+                        if ($mode === 'sync') {
+                            $relation->sync($value);
+                        } else {
+                            $relation->syncWithoutDetaching($value);
+                        }
+
                         break;
                 }
             }