diff --git a/lib/sendgrid.rb b/lib/sendgrid.rb
index 688493d..2322092 100644
--- a/lib/sendgrid.rb
+++ b/lib/sendgrid.rb
@@ -28,7 +28,7 @@ class << self
                       :default_footer_text, :default_spamcheck_score, :default_sg_unique_args
       end
       attr_accessor :sg_category, :sg_options, :sg_disabled_options, :sg_recipients, :sg_substitutions,
-                    :subscriptiontrack_text, :footer_text, :spamcheck_score, :sg_unique_args
+                    :subscriptiontrack_text, :footer_text, :spamcheck_score, :sg_unique_args, :sg_pool
     end
 
     # NOTE: This commented-out approach may be a "safer" option for Rails 3, but it
@@ -103,6 +103,16 @@ def sendgrid_category(category)
     @sg_category = category
   end
 
+  # Call within mailer method to concatenate sendgrid categories.
+  # Will not remove duplicates.
+  def append_sendgrid_category(category)
+    @sg_category = (@sg_category || []) + category
+  end
+
+  def sendgrid_pool(pool_name)
+    @sg_pool = pool_name
+  end
+
   # Call within mailer method to set unique args for this email.
   # Merged with class-level unique args, if any exist.
   def sendgrid_unique_args(unique_args = {})
@@ -210,6 +220,9 @@ def sendgrid_json_headers(mail)
       header_opts[:unique_args] = unique_args unless unique_args.empty?
     end
 
+    # Set pool
+    header_opts[:ip_pool] = @sg_pool if @sg_pool
+
     # Set category
     if @sg_category && @sg_category == :use_subject_lines
       header_opts[:category] = mail.subject
diff --git a/sendgrid.gemspec b/sendgrid.gemspec
index 0df55dd..c699265 100644
--- a/sendgrid.gemspec
+++ b/sendgrid.gemspec
@@ -42,20 +42,17 @@ Gem::Specification.new do |s|
       s.add_development_dependency(%q<shoulda>, [">= 0"])
       s.add_development_dependency(%q<bundler>, ["~> 1.0.0"])
       s.add_development_dependency(%q<jeweler>, ["~> 1.5.1"])
-      s.add_runtime_dependency(%q<json>, [">= 0"])
     else
       s.add_dependency(%q<json>, [">= 0"])
       s.add_dependency(%q<shoulda>, [">= 0"])
       s.add_dependency(%q<bundler>, ["~> 1.0.0"])
       s.add_dependency(%q<jeweler>, ["~> 1.5.1"])
-      s.add_dependency(%q<json>, [">= 0"])
     end
   else
     s.add_dependency(%q<json>, [">= 0"])
     s.add_dependency(%q<shoulda>, [">= 0"])
     s.add_dependency(%q<bundler>, ["~> 1.0.0"])
     s.add_dependency(%q<jeweler>, ["~> 1.5.1"])
-    s.add_dependency(%q<json>, [">= 0"])
   end
 end