diff --git a/lib/rack/attack/store_proxy.rb b/lib/rack/attack/store_proxy.rb
index de0bc0c..5ce0f52 100644
--- a/lib/rack/attack/store_proxy.rb
+++ b/lib/rack/attack/store_proxy.rb
@@ -1,7 +1,7 @@
 module Rack
   class Attack
     module StoreProxy
-      PROXIES = [DalliProxy, MemCacheProxy, RedisStoreProxy]
+      PROXIES = [DalliProxy, MemCacheProxy, RedisStoreProxy].freeze
 
       ACTIVE_SUPPORT_WRAPPER_CLASSES = Set.new(['ActiveSupport::Cache::MemCacheStore', 'ActiveSupport::Cache::RedisStore']).freeze
       ACTIVE_SUPPORT_CLIENTS = Set.new(['Redis::Store', 'Dalli::Client', 'MemCache']).freeze
diff --git a/lib/rack/attack/throttle.rb b/lib/rack/attack/throttle.rb
index 5af953c..19a6519 100644
--- a/lib/rack/attack/throttle.rb
+++ b/lib/rack/attack/throttle.rb
@@ -1,7 +1,8 @@
 module Rack
   class Attack
     class Throttle
-      MANDATORY_OPTIONS = [:limit, :period]
+      MANDATORY_OPTIONS = [:limit, :period].freeze
+
       attr_reader :name, :limit, :period, :block, :type
       def initialize(name, options, block)
         @name, @block = name, block