diff --git a/composer.json b/composer.json
index 7613857..d9da03e 100644
--- a/composer.json
+++ b/composer.json
@@ -16,7 +16,7 @@
         "phpunit/phpunit": "~4.0"
     },
     "require": {
-        "texthtml/php-lock": "~2.0",
+        "texthtml/php-lock": "~2.1",
         "predis/predis": "~1.0",
         "psr/log": "~1.0"
     }
diff --git a/src/RedisSimpleLockFactory.php b/src/RedisSimpleLockFactory.php
index abcb887..719caa7 100644
--- a/src/RedisSimpleLockFactory.php
+++ b/src/RedisSimpleLockFactory.php
@@ -5,8 +5,9 @@
 use Predis\Client;
 use Psr\Log\LoggerInterface;
 use Psr\Log\NullLogger;
+use TH\Lock\TtlFactory;
 
-class RedisSimpleLockFactory
+class RedisSimpleLockFactory implements TtlFactory
 {
     private $client;
     private $defaultTtl;