diff --git a/README.rst b/README.rst
index 8bcd748..3881dd1 100644
--- a/README.rst
+++ b/README.rst
@@ -52,6 +52,17 @@ Example: 600 requests per minute
     except TooManyRequests:
       return '429 Too Many Requests'
 
+Example: 1 request per 50 milliseconds
+
+.. code-block:: python
+
+    from redis_rate_limit import RateLimit, TooManyRequests, TimeUnit
+    try:
+      with RateLimit(resource='users_list', client='192.168.0.10', max_requests=1, expire=50, time_unit=TimeUnit.MILLISECOND):
+        return '200 OK'
+    except TooManyRequests:
+      return '429 Too Many Requests'
+
 Example: 100 requests per hour
 
 .. code-block:: python
diff --git a/redis_rate_limit/__init__.py b/redis_rate_limit/__init__.py
index b08e96d..1750713 100644
--- a/redis_rate_limit/__init__.py
+++ b/redis_rate_limit/__init__.py
@@ -7,19 +7,26 @@
 from redis.exceptions import NoScriptError
 from redis import Redis, ConnectionPool
 
+from enum import Enum
+
+
+class TimeUnit(Enum):
+    SECOND = "second"
+    MILLISECOND = "millisecond"
+
 
 # Adapted from http://redis.io/commands/incr#pattern-rate-limiter-2
 INCREMENT_SCRIPT = b"""
     local current
     current = tonumber(redis.call("incrby", KEYS[1], ARGV[2]))
     if current == tonumber(ARGV[2]) then
-        redis.call("expire", KEYS[1], ARGV[1])
+        redis.call("PEXPIRE", KEYS[1], ARGV[1])
     end
     return current
 """
 INCREMENT_SCRIPT_HASH = sha1(INCREMENT_SCRIPT).hexdigest()
 
-REDIS_POOL = ConnectionPool(host='127.0.0.1', port=6379, db=0)
+REDIS_POOL = ConnectionPool(host="127.0.0.1", port=6379, db=0)
 
 
 class RedisVersionNotSupported(Exception):
@@ -27,6 +34,7 @@ class RedisVersionNotSupported(Exception):
     Rate Limit depends on Redis’ commands EVALSHA and EVAL which are
     only available since the version 2.6.0 of the database.
     """
+
     pass
 
 
@@ -35,6 +43,7 @@ class TooManyRequests(Exception):
     Occurs when the maximum number of requests is reached for a given resource
     of an specific user.
     """
+
     pass
 
 
@@ -43,7 +52,16 @@ class RateLimit(object):
     This class offers an abstraction of a Rate Limit algorithm implemented on
     top of Redis >= 2.6.0.
     """
-    def __init__(self, resource, client, max_requests, expire=None, redis_pool=REDIS_POOL):
+
+    def __init__(
+        self,
+        resource,
+        client,
+        max_requests,
+        expire=None,
+        redis_pool=REDIS_POOL,
+        time_unit: TimeUnit = TimeUnit.SECOND,
+    ):
         """
         Class initialization method checks if the Rate Limit algorithm is
         actually supported by the installed Redis version and sets some
@@ -65,6 +83,7 @@ def __init__(self, resource, client, max_requests, expire=None, redis_pool=REDIS
         self._rate_limit_key = "rate_limit:{0}_{1}".format(resource, client)
         self._max_requests = max_requests
         self._expire = expire or 1
+        self._expire = expire * 1000 if time_unit == TimeUnit.SECOND else expire
 
     def __call__(self, func):
         """
@@ -130,21 +149,32 @@ def increment_usage(self, increment_by=1):
         :return: integer: current usage
         """
         if increment_by > self._max_requests:
-            raise ValueError('increment_by {increment_by} overflows '
-                             'max_requests of {max_requests}'
-                             .format(increment_by=increment_by, 
-                                     max_requests=self._max_requests))
+            raise ValueError(
+                "increment_by {increment_by} overflows "
+                "max_requests of {max_requests}".format(
+                    increment_by=increment_by, max_requests=self._max_requests
+                )
+            )
         elif increment_by <= 0:
-            raise ValueError('{increment_by} is not a valid increment, '
-                             'should be greater than or equal to zero.'
-                             .format(increment_by=increment_by))
+            raise ValueError(
+                "{increment_by} is not a valid increment, "
+                "should be greater than or equal to zero.".format(
+                    increment_by=increment_by
+                )
+            )
 
         try:
             current_usage = self._redis.evalsha(
-                INCREMENT_SCRIPT_HASH, 1, self._rate_limit_key, self._expire, increment_by)
+                INCREMENT_SCRIPT_HASH,
+                1,
+                self._rate_limit_key,
+                self._expire,
+                increment_by,
+            )
         except NoScriptError:
             current_usage = self._redis.eval(
-                INCREMENT_SCRIPT, 1, self._rate_limit_key, self._expire, increment_by)
+                INCREMENT_SCRIPT, 1, self._rate_limit_key, self._expire, increment_by
+            )
 
         if int(current_usage) > self._max_requests:
             raise TooManyRequests()
@@ -160,13 +190,14 @@ def _is_rate_limit_supported(self):
         """
         redis_version = self._redis.info()['redis_version']
         is_supported = Version(redis_version) >= Version('2.6.0')
+
         return bool(is_supported)
 
     def _reset(self):
         """
         Deletes all keys that start with ‘rate_limit:’.
         """
-        matching_keys = self._redis.scan_iter(match='{0}*'.format('rate_limit:*'))
+        matching_keys = self._redis.scan_iter(match="{0}*".format("rate_limit:*"))
         for rate_limit_key in matching_keys:
             self._redis.delete(rate_limit_key)
 
@@ -180,7 +211,7 @@ def __init__(self, resource, max_requests, expire=None, redis_pool=REDIS_POOL):
         :param expire: seconds to wait before resetting counters (i.e. ‘60’)
         :param redis_pool: instance of redis.ConnectionPool.
                Default: ConnectionPool(host='127.0.0.1', port=6379, db=0)
-       """
+        """
         self.resource = resource
         self.max_requests = max_requests
         self.expire = expire