diff --git a/AUTHORS.rst b/AUTHORS.rst
index ab82930b..52bfc350 100644
--- a/AUTHORS.rst
+++ b/AUTHORS.rst
@@ -151,4 +151,5 @@ Patches and Suggestions
 - Kamil Madac <kamil.madac@gmail.com>
 - Michael Becker <mike@beckerfuffle.com> @beckerfuffle
 - Erik Wickstrom <erik@erikwickstrom.com> @erikwickstrom
-- Константин Подшумок @podshumok
\ No newline at end of file
+- Константин Подшумок @podshumok
+- Ben Bass @codedstructure
diff --git a/requests/adapters.py b/requests/adapters.py
index eb7a2d28..0e20bd1c 100644
--- a/requests/adapters.py
+++ b/requests/adapters.py
@@ -101,14 +101,17 @@ class HTTPAdapter(BaseAdapter):
         self.init_poolmanager(self._pool_connections, self._pool_maxsize,
                               block=self._pool_block)
 
-    def init_poolmanager(self, connections, maxsize, block=DEFAULT_POOLBLOCK):
-        """Initializes a urllib3 PoolManager. This method should not be called
-        from user code, and is only exposed for use when subclassing the
+    def init_poolmanager(self, connections, maxsize, block=DEFAULT_POOLBLOCK, **pool_kwargs):
+        """Initializes a urllib3 PoolManager.
+
+        This method should not be called from user code, and is only
+        exposed for use when subclassing the
         :class:`HTTPAdapter <requests.adapters.HTTPAdapter>`.
 
         :param connections: The number of urllib3 connection pools to cache.
         :param maxsize: The maximum number of connections to save in the pool.
         :param block: Block when no free connections are available.
+        :param pool_kwargs: Extra keyword arguments used to initialize the Pool Manager.
         """
         # save these values for pickling
         self._pool_connections = connections
@@ -116,7 +119,30 @@ class HTTPAdapter(BaseAdapter):
         self._pool_block = block
 
         self.poolmanager = PoolManager(num_pools=connections, maxsize=maxsize,
-                                       block=block)
+                                       block=block, **pool_kwargs)
+
+    def proxy_manager_for(self, proxy, **proxy_kwargs):
+        """Return urllib3 ProxyManager for the given proxy.
+
+        This method should not be called from user code, and is only
+        exposed for use when subclassing the
+        :class:`HTTPAdapter <requests.adapters.HTTPAdapter>`.
+
+        :param proxy: The proxy to return a urllib3 ProxyManager for.
+        :param proxy_kwargs: Extra keyword arguments used to configure the Proxy Manager.
+        :returns: ProxyManager
+        """
+        if not proxy in self.proxy_manager:
+            proxy_headers = self.proxy_headers(proxy)
+            self.proxy_manager[proxy] = proxy_from_url(
+                proxy,
+                proxy_headers=proxy_headers,
+                num_pools=self._pool_connections,
+                maxsize=self._pool_maxsize,
+                block=self._pool_block,
+                **proxy_kwargs)
+
+        return self.proxy_manager[proxy]
 
     def cert_verify(self, conn, url, verify, cert):
         """Verify a SSL certificate. This method should not be called from user
@@ -204,17 +230,8 @@ class HTTPAdapter(BaseAdapter):
 
         if proxy:
             proxy = prepend_scheme_if_needed(proxy, 'http')
-            proxy_headers = self.proxy_headers(proxy)
-
-            if not proxy in self.proxy_manager:
-                self.proxy_manager[proxy] = proxy_from_url(
-                                                proxy,
-                                                proxy_headers=proxy_headers,
-                                                num_pools=self._pool_connections,
-                                                maxsize=self._pool_maxsize,
-                                                block=self._pool_block)
-
-            conn = self.proxy_manager[proxy].connection_from_url(url)
+            proxy_manager = self.proxy_manager_for(proxy)
+            conn = proxy_manager.connection_from_url(url)
         else:
             # Only scheme should be lower case
             parsed = urlparse(url)