diff --git a/doc/jsk_topic_tools/scripts/synchronize_republish.rst b/doc/jsk_topic_tools/scripts/synchronize_republish.rst
index 5900edd61..81ef3b047 100644
--- a/doc/jsk_topic_tools/scripts/synchronize_republish.rst
+++ b/doc/jsk_topic_tools/scripts/synchronize_republish.rst
@@ -35,6 +35,10 @@ Parameters
 
   If ``true``, approximate synchronization is used for synchoronizing assigned topics.
 
+* ``~allow_headerless`` (Bool, Default: ``false``)
+
+  If ``true``, ``allow_headerless`` option of approximate synchronization is enabled.
+
 * ``~queue_size`` (Integer, Default: ``100``)
 
   Queue length for subscribing topics.
diff --git a/jsk_data/src/jsk_data/download_data.py b/jsk_data/src/jsk_data/download_data.py
index 2bd7bca6c..e3dc4f211 100644
--- a/jsk_data/src/jsk_data/download_data.py
+++ b/jsk_data/src/jsk_data/download_data.py
@@ -31,6 +31,8 @@ def extract_file(path, to_directory='.', chmod=True):
         opener, mode, getnames = zipfile.ZipFile, 'r', lambda f: f.namelist()
     elif path.endswith('.tar.gz') or path.endswith('.tgz'):
         opener, mode, getnames = tarfile.open, 'r:gz', lambda f: f.getnames()
+    elif path.endswith('.tar.xz'):
+        opener, mode, getnames = tarfile.open, 'r:xz', lambda f: f.getnames()
     elif path.endswith('.tar.bz2') or path.endswith('.tbz'):
         opener, mode, getnames = tarfile.open, 'r:bz2', lambda f: f.getnames()
     else:
diff --git a/jsk_topic_tools/scripts/synchronize_republish.py b/jsk_topic_tools/scripts/synchronize_republish.py
index 3da1959ce..96e6a5ed4 100755
--- a/jsk_topic_tools/scripts/synchronize_republish.py
+++ b/jsk_topic_tools/scripts/synchronize_republish.py
@@ -9,10 +9,13 @@
 def callback(*msgs):
     stamp = None
     for msg, pub in zip(msgs, pubs):
-        if stamp is None:
-            stamp = msg.header.stamp
-        else:
-            msg.header.stamp = stamp
+        try:
+            if stamp is None:
+                stamp = msg.header.stamp
+            else:
+                msg.header.stamp = stamp
+        except AttributeError:
+            pass
         pub.publish(msg)
 
 
@@ -20,6 +23,7 @@ def callback(*msgs):
     rospy.init_node('synchrnoze_republish')
     topics = rospy.get_param('~topics')
     use_async = rospy.get_param('~approximate_sync', False)
+    allow_headerless = rospy.get_param('~allow_headerless', False)
     queue_size = rospy.get_param('~queue_size', 100)
     slop = rospy.get_param('~slop', 0.1)
     pubs = []
@@ -34,7 +38,7 @@ def callback(*msgs):
         subs.append(sub)
     if use_async:
         sync = message_filters.ApproximateTimeSynchronizer(
-            subs, queue_size=queue_size, slop=slop)
+            subs, queue_size=queue_size, slop=slop, allow_headerless=allow_headerless)
     else:
         sync = message_filters.TimeSynchronizer(subs, queue_size=queue_size)
     sync.registerCallback(callback)