diff --git a/brother_ql/backends/generic.py b/brother_ql/backends/generic.py
index b638e8a..bfcd4d4 100644
--- a/brother_ql/backends/generic.py
+++ b/brother_ql/backends/generic.py
@@ -1,4 +1,6 @@
 
+from builtins import bytes
+
 import logging
 
 logger = logging.getLogger(__name__)
diff --git a/brother_ql/backends/pyusb.py b/brother_ql/backends/pyusb.py
index 3217b75..bce5f88 100755
--- a/brother_ql/backends/pyusb.py
+++ b/brother_ql/backends/pyusb.py
@@ -9,7 +9,7 @@
 """
 
 from __future__ import unicode_literals
-from builtins import str
+from builtins import str, bytes
 
 import time