diff --git a/lib/logstash/filters/handsetdetection.rb b/lib/logstash/filters/handsetdetection.rb
index c5e4d4f..40ecc2f 100644
--- a/lib/logstash/filters/handsetdetection.rb
+++ b/lib/logstash/filters/handsetdetection.rb
@@ -1,9 +1,33 @@
-# encoding: utf-8
+#--
+# Copyright (c) Richard Uren 2016 <richard@teleport.com.au>
+# All Rights Reserved
+#
+# LICENSE: Redistribution and use in source and binary forms, with or
+# without modification, are permitted provided that the following
+# conditions are met: Redistributions of source code must retain the
+# above copyright notice, this list of conditions and the following
+# disclaimer. Redistributions in binary form must reproduce the above
+# copyright notice, this list of conditions and the following disclaimer
+# in the documentation and/or other materials provided with the
+# distribution.
+#
+# THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
+# WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+# MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN
+# NO EVENT SHALL CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+# INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+# BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+# OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+# ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR
+# TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE
+# USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
+# DAMAGE.
+#++
+
 require 'logstash/filters/base'
 require 'logstash/namespace'
 require 'handset_detection'
 
-
 class LogStash::Filters::HandsetDetection < LogStash::Filters::Base
 
   config_name 'handsetdetection'
@@ -45,13 +69,14 @@ def register
     @hd_config['log_unknown'] = true 
     @hd_config['local_archive_source'] = @local_archive_source 
 
+    @@pool = []
     unless @online_api
       hd = HD4.new @hd_config
       hd.set_timeout 500
       hd.device_fetch_archive
       hd.set_timeout 30
+      @@pool << hd
     end
-    @pool = [ hd ]
   end
 
   public
@@ -62,11 +87,11 @@ def filter(event)
         data[dest] = event[src]
       end
     end 
-    hd = @pool.pop
+    hd = @@pool.pop
     hd = HD4.new @hd_config if hd.nil?
     hd.device_detect data
     r = hd.get_reply
-    @pool << hd
+    @@pool << hd
     if r.key? 'class'
       event['handset_class'] = r['class']
     end
diff --git a/logstash-filter-handsetdetection.gemspec b/logstash-filter-handsetdetection.gemspec
index bc6b35c..7a755da 100644
--- a/logstash-filter-handsetdetection.gemspec
+++ b/logstash-filter-handsetdetection.gemspec
@@ -20,7 +20,7 @@ Gem::Specification.new do |s|
   # Gem dependencies
   s.add_runtime_dependency "logstash-core", ">= 2.0.0", "< 3.0.0"
   s.add_runtime_dependency "json", "~> 1.8"
-  s.add_runtime_dependency "handset_detection", "~> 0.1", ">= 0.1.7"
+  s.add_runtime_dependency "handset_detection", "~> 0.1", ">= 0.1.8"
 
   #s.add_development_dependency 'logstash-devutils'
 end