diff --git a/CHANGELOG.md b/CHANGELOG.md
index 5dbf009..5423cd8 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -11,3 +11,4 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - initial implementation
     - can create a custom Logger instance rotating or static
     - combined logger (OXID and configured stream)
+    - can combine with special handlers (buffered, onErrorOnly, deduplicated)
diff --git a/README.md b/README.md
index daf4899..b9d5503 100644
--- a/README.md
+++ b/README.md
@@ -15,8 +15,36 @@ composer require d3/logger-factory
 ## Usage
 
 ```
-$loggerFactory = loggerFactory::create();
-$logger = $loggerFactory->getFileLogger('myPluginLogger', 'plugin_requests.log', Logger::DEBUG, 5);
+use D3\LoggerFactory\LoggerFactory;
+
+$loggerFactory = LoggerFactory::create();
+$logger = $loggerFactory->getFileLogger(
+    'myPluginLogger', 
+    'plugin_requests.log', 
+    Logger::DEBUG, 
+    5
+);
+```
+
+### Use of the special handler
+
+```
+use D3\LoggerFactory\LoggerFactory;
+
+$loggerFactory = LoggerFactory::create();
+$logger = $loggerFactory->getFileLogger(
+    'myPluginLogger', 
+    'plugin_requests.log', 
+    Logger::DEBUG, 
+    5, 
+    [
+        LoggerFactory::SPECIAL_HANDLERS_LOG_ON_ERROR_ONLY,      // simple default implementation
+        LoggerFactory::SPECIAL_HANDLERS_BUFFERING,
+        LoggerFactory::SPECIAL_HANDLERS_MAKE_UNIQUE => [        // advanced custom implementation
+            LoggerFactory::MAKEUNIQUE_OPTION_LEVEL => Logger::INFO
+        ],
+    ]
+);
 ```
 
 ## Licence of this software (Logger factory) [MIT]
diff --git a/src/LoggerFactory.php b/src/LoggerFactory.php
index 2408858..0b252ef 100644
--- a/src/LoggerFactory.php
+++ b/src/LoggerFactory.php
@@ -18,8 +18,10 @@ declare(strict_types=1);
 namespace D3\LoggerFactory;
 
 use Exception;
+use Monolog\Handler\AbstractHandler;
 use Monolog\Handler\AbstractProcessingHandler;
 use Monolog\Handler\BufferHandler;
+use Monolog\Handler\DeduplicationHandler;
 use Monolog\Handler\FingersCrossed\ErrorLevelActivationStrategy;
 use Monolog\Handler\FingersCrossedHandler;
 use Monolog\Handler\RotatingFileHandler;
@@ -32,6 +34,15 @@ class LoggerFactory
 {
     public const SPECIAL_HANDLERS_BUFFERING = 'buffering';
     public const SPECIAL_HANDLERS_LOG_ON_ERROR_ONLY = 'logOnErrorOnly';
+    public const SPECIAL_HANDLERS_MAKE_UNIQUE = 'makeUnique';
+
+    public const BUFFERING_OPTION_LIMIT = 'bufferLimit';
+    public const BUFFERING_OPTION_LEVEL = 'loglevel';
+
+    public const LOGONERRORONLY_LEVEL   = 'activationLevel';
+
+    public const MAKEUNIQUE_OPTION_LEVEL = 'loglevel';
+    public const MAKEUNIQUE_OPTION_TIME = 'time';
 
     public static function create(): LoggerFactory
     {
@@ -117,25 +128,54 @@ class LoggerFactory
     public function applySpecialHandlers(
         AbstractProcessingHandler $handler,
         array $specialHandlers = []
-    ): AbstractProcessingHandler
+    ): AbstractHandler
     {
         if (in_array(self::SPECIAL_HANDLERS_BUFFERING, $specialHandlers, true)) {
-            $handler = $this->setLogItemsOnErrorOnly($handler);
+            $handler = $this->setBuffering($handler);
+        } elseif (in_array(self::SPECIAL_HANDLERS_BUFFERING, array_keys($specialHandlers), true)) {
+            $options = $specialHandlers[self::SPECIAL_HANDLERS_BUFFERING];
+            $handler = $this->setBuffering(
+                $handler,
+                $options[self::BUFFERING_OPTION_LIMIT] ?? 0,
+                $options[self::BUFFERING_OPTION_LEVEL] ?? Logger::DEBUG
+            );
         }
+
         if (in_array(self::SPECIAL_HANDLERS_LOG_ON_ERROR_ONLY, $specialHandlers, true)) {
             $handler = $this->setLogItemsOnErrorOnly($handler);
+        } elseif (in_array(self::SPECIAL_HANDLERS_LOG_ON_ERROR_ONLY, array_keys($specialHandlers), true)) {
+            $options = $specialHandlers[self::SPECIAL_HANDLERS_LOG_ON_ERROR_ONLY];
+            $handler = $this->setLogItemsOnErrorOnly(
+                $handler,
+                $options[self::LOGONERRORONLY_LEVEL] ?? Logger::ERROR
+            );
+        }
+
+        if (in_array(self::SPECIAL_HANDLERS_MAKE_UNIQUE, $specialHandlers, true)) {
+            $handler = $this->makeUnique($handler);
+        } elseif (in_array(self::SPECIAL_HANDLERS_MAKE_UNIQUE, array_keys($specialHandlers), true)) {
+            $options = $specialHandlers[self::SPECIAL_HANDLERS_MAKE_UNIQUE];
+            $handler = $this->makeUnique(
+                $handler,
+                $options[self::MAKEUNIQUE_OPTION_LEVEL] ?? Logger::ERROR,
+                $options[self::MAKEUNIQUE_OPTION_TIME] ?? 60
+            );
         }
 
         return $handler;
     }
 
-    public function setBuffering(AbstractProcessingHandler $handler): BufferHandler
+    public function setBuffering(
+        AbstractHandler $handler,
+        int $bufferLimit = 0,
+        int $loglevel = Logger::DEBUG
+    ): BufferHandler
     {
-        return new BufferHandler($handler);
+        return new BufferHandler($handler, $bufferLimit, $loglevel);
     }
 
     public function setLogItemsOnErrorOnly(
-        AbstractProcessingHandler $handler,
+        AbstractHandler $handler,
         int $activationLevel = Logger::ERROR
     ): FingersCrossedHandler
     {
@@ -144,4 +184,13 @@ class LoggerFactory
             new ErrorLevelActivationStrategy($activationLevel)
         );
     }
+
+    public function makeUnique(
+        AbstractHandler $handler,
+        int $deduplicationLevel = Logger::ERROR,
+        int $time = 60
+    ): DeduplicationHandler
+    {
+        return new DeduplicationHandler($handler, null, $deduplicationLevel, $time);
+    }
 }
\ No newline at end of file
diff --git a/tests/LoggerFactoryTest.php b/tests/LoggerFactoryTest.php
index a673741..b30e555 100644
--- a/tests/LoggerFactoryTest.php
+++ b/tests/LoggerFactoryTest.php
@@ -4,6 +4,9 @@ namespace D3\LoggerFactory\tests;
 
 use D3\LoggerFactory\LoggerFactory;
 use Generator;
+use Monolog\Handler\BufferHandler;
+use Monolog\Handler\DeduplicationHandler;
+use Monolog\Handler\FingersCrossedHandler;
 use Monolog\Handler\RotatingFileHandler;
 use Monolog\Handler\StreamHandler;
 use Monolog\Logger;
@@ -34,7 +37,10 @@ class LoggerFactoryTest extends ApiTestCase
      */
     public function testGetFileLogger(int $logLevel, ?int $maxFiles, string $expectedHandlerClass): void
     {
-        $sut = LoggerFactory::create();
+        $sut = $this->getMockBuilder(LoggerFactory::class)
+            ->onlyMethods(['applySpecialHandlers'])
+            ->getMock();
+        $sut->expects($this->once())->method('applySpecialHandlers')->willReturnArgument(0);
 
         /** @var Logger|MockObject $logger */
         $logger = $this->callMethod(
@@ -63,7 +69,10 @@ class LoggerFactoryTest extends ApiTestCase
      */
     public function testGetCombinedOxidAndFileLoggerWithoutOxid(): void
     {
-        $sut = LoggerFactory::create();
+        $sut = $this->getMockBuilder(LoggerFactory::class)
+            ->onlyMethods(['applySpecialHandlers'])
+            ->getMock();
+        $sut->expects($this->never())->method('applySpecialHandlers')->willReturnArgument(0);
 
         $this->expectException(RuntimeException::class);
 
@@ -102,11 +111,14 @@ class LoggerFactoryTest extends ApiTestCase
      * @throws ReflectionException
      * @covers \D3\LoggerFactory\LoggerFactory::getCombinedOxidAndFileLogger
      */
-    public function testAddCombinedOxidAndFileLoggerInOxid(): void
+    public function testGetCombinedOxidAndFileLoggerInOxid(): void
     {
         require_once __DIR__.'/Helpers/classAliases.php';
 
-        $sut = LoggerFactory::create();
+        $sut = $this->getMockBuilder(LoggerFactory::class)
+            ->onlyMethods(['applySpecialHandlers'])
+            ->getMock();
+        $sut->expects($this->exactly(2))->method('applySpecialHandlers')->willReturnArgument(0);
 
         $logger = $this->callMethod(
             $sut,
@@ -138,4 +150,117 @@ class LoggerFactoryTest extends ApiTestCase
             )
         );
     }
+
+    /**
+     * @test
+     * @covers \D3\LoggerFactory\LoggerFactory::applySpecialHandlers
+     * @throws ReflectionException
+     * @dataProvider applySpecialHandlersDataProvider
+     */
+    public function testApplySpecialHandlers(array $options, string $expectedClass): void
+    {
+        $sut = LoggerFactory::create();
+
+        $handler = $this->getMockBuilder(StreamHandler::class)
+            ->disableOriginalConstructor()
+            ->getMock();
+
+        $this->assertInstanceOf(
+            $expectedClass,
+            $this->callMethod(
+                $sut,
+                'applySpecialHandlers',
+                [$handler, $options]
+            )
+        );
+    }
+
+    public static function applySpecialHandlersDataProvider(): Generator
+    {
+        yield 'empty config' => [[], StreamHandler::class];
+        yield 'simple buffering' => [[LoggerFactory::SPECIAL_HANDLERS_BUFFERING], BufferHandler::class];
+        yield 'advanced buffering' => [
+            [LoggerFactory::SPECIAL_HANDLERS_BUFFERING   => [LoggerFactory::BUFFERING_OPTION_LIMIT => 10]],
+            BufferHandler::class
+        ];
+        yield 'simple logOnErrorOnly' => [[LoggerFactory::SPECIAL_HANDLERS_LOG_ON_ERROR_ONLY], FingersCrossedHandler::class];
+        yield 'advanced logOnErrorOnly' => [
+            [LoggerFactory::SPECIAL_HANDLERS_LOG_ON_ERROR_ONLY   => [LoggerFactory::LOGONERRORONLY_LEVEL => Logger::DEBUG]],
+            FingersCrossedHandler::class
+        ];
+        yield 'simple deduplicate' => [[LoggerFactory::SPECIAL_HANDLERS_MAKE_UNIQUE], DeduplicationHandler::class];
+        yield 'advanced deduplicate' => [
+            [LoggerFactory::SPECIAL_HANDLERS_MAKE_UNIQUE   => [LoggerFactory::MAKEUNIQUE_OPTION_TIME => 30]],
+            DeduplicationHandler::class
+        ];
+    }
+
+    /**
+     * @test
+     * @throws ReflectionException
+     * @covers \D3\LoggerFactory\LoggerFactory::setBuffering
+     */
+    public function testSetBuffering(): void
+    {
+        $sut = LoggerFactory::create();
+
+        $handler = $this->getMockBuilder(StreamHandler::class)
+            ->disableOriginalConstructor()
+            ->getMock();
+
+        $this->assertInstanceOf(
+            BufferHandler::class,
+            $this->callMethod(
+                $sut,
+                'setBuffering',
+                [$handler]
+            )
+        );
+    }
+
+    /**
+     * @test
+     * @throws ReflectionException
+     * @covers \D3\LoggerFactory\LoggerFactory::setLogItemsOnErrorOnly
+     */
+    public function testSetLogItemsOnErrorOnly(): void
+    {
+        $sut = LoggerFactory::create();
+
+        $handler = $this->getMockBuilder(StreamHandler::class)
+            ->disableOriginalConstructor()
+            ->getMock();
+
+        $this->assertInstanceOf(
+            FingersCrossedHandler::class,
+            $this->callMethod(
+                $sut,
+                'setLogItemsOnErrorOnly',
+                [$handler]
+            )
+        );
+    }
+
+    /**
+     * @test
+     * @throws ReflectionException
+     * @covers \D3\LoggerFactory\LoggerFactory::makeUnique
+     */
+    public function testMakeUnique(): void
+    {
+        $sut = LoggerFactory::create();
+
+        $handler = $this->getMockBuilder(StreamHandler::class)
+            ->disableOriginalConstructor()
+            ->getMock();
+
+        $this->assertInstanceOf(
+            DeduplicationHandler::class,
+            $this->callMethod(
+                $sut,
+                'makeUnique',
+                [$handler]
+            )
+        );
+    }
 }
\ No newline at end of file