diff --git a/CHANGELOG.md b/CHANGELOG.md
index dd82478..ec0c52c 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,8 @@
 # PyProbables Changelog
 
+### Version 0.2.0
+* Use __slots__
+
 ### Version 0.1.4:
 * Drop support for python 3.3
 * Ensure passing parameters correctly to parent classes
diff --git a/probables/__init__.py b/probables/__init__.py
index e186a5e..4ce2e52 100644
--- a/probables/__init__.py
+++ b/probables/__init__.py
@@ -11,7 +11,7 @@
 __maintainer__ = 'Tyler Barrus'
 __email__ = 'barrust@gmail.com'
 __license__ = 'MIT'
-__version__ = '0.1.4'
+__version__ = '0.2.0'
 __credits__ = []
 __url__ = 'https://github.com/barrust/pyprobables'
 __bugtrack_url__ = 'https://github.com/barrust/pyprobables/issues'
diff --git a/probables/blooms/basebloom.py b/probables/blooms/basebloom.py
index 83053d3..1302dc6 100644
--- a/probables/blooms/basebloom.py
+++ b/probables/blooms/basebloom.py
@@ -19,6 +19,13 @@
 
 class BaseBloom(object):
     ''' basic bloom filter object '''
+
+    __slots__ = [
+        '_bloom', '__num_bits', '__est_elements', '__fpr',
+        '__number_hashes', '__hash_func', '_els_added', '_on_disk',
+        '__impt_type', '__blm_type', '__bloom_length'
+    ]
+
     def __init__(self, blm_type, est_elements=None, false_positive_rate=None,
                  filepath=None, hex_string=None, hash_function=None):
         ''' setup the basic values needed '''
diff --git a/probables/blooms/bloom.py b/probables/blooms/bloom.py
index 08d357e..4727076 100644
--- a/probables/blooms/bloom.py
+++ b/probables/blooms/bloom.py
@@ -86,6 +86,8 @@ class BloomFilter(BaseBloom):
                 2) From Hex String
                 3) From params '''
 
+    __slots__ = []
+
     def __init__(self, est_elements=None, false_positive_rate=None,
                  filepath=None, hex_string=None, hash_function=None):
         ''' setup the basic values needed '''
diff --git a/probables/blooms/countingbloom.py b/probables/blooms/countingbloom.py
index 76cc009..df0b76a 100644
--- a/probables/blooms/countingbloom.py
+++ b/probables/blooms/countingbloom.py
@@ -39,6 +39,9 @@ class CountingBloomFilter(BaseBloom):
                 1) From file
                 2) From Hex String
                 3) From params '''
+
+    __slots__ = BaseBloom.__slots__
+
     def __init__(self, est_elements=None, false_positive_rate=None,
                  filepath=None, hex_string=None, hash_function=None):
         ''' setup the basic values needed '''
diff --git a/probables/countminsketch/countminsketch.py b/probables/countminsketch/countminsketch.py
index 14918c5..9a5b0fb 100644
--- a/probables/countminsketch/countminsketch.py
+++ b/probables/countminsketch/countminsketch.py
@@ -43,6 +43,11 @@ class CountMinSketch(object):
             For width and depth, width may realistically be in the thousands \
             while depth is in the single digit to teens '''
 
+    __slots__ = [
+        '__width', '__depth', '__confidence', '__error_rate',
+        '__elements_added', '__query_method', '_bins', '_hash_function'
+    ]
+
     def __init__(self, width=None, depth=None, confidence=None,
                  error_rate=None, filepath=None, hash_function=None):
         ''' default initilization function '''
@@ -373,6 +378,9 @@ class CountMeanSketch(CountMinSketch):
         Note:
             For width and depth, width may realistically be in the thousands \
             while depth is in the single digit to teens  '''
+
+    __slots__ = CountMinSketch.__slots__
+
     def __init__(self, width=None, depth=None, confidence=None,
                  error_rate=None, filepath=None, hash_function=None):
         super(CountMeanSketch, self).__init__(width, depth, confidence,
@@ -406,6 +414,9 @@ class CountMeanMinSketch(CountMinSketch):
         Note:
             For width and depth, width may realistically be in the thousands \
             while depth is in the single digit to teens  '''
+
+    __slots__ = CountMinSketch.__slots__
+
     def __init__(self, width=None, depth=None, confidence=None,
                  error_rate=None, filepath=None, hash_function=None):
         super(CountMeanMinSketch, self).__init__(width, depth, confidence,
@@ -440,6 +451,9 @@ class HeavyHitters(CountMinSketch):
             For width and depth, width may realistically be in the thousands \
             while depth is in the single digit to teens  '''
 
+    __slots__ = CountMinSketch.__slots__
+    __slots__.extend(['__top_x', '__top_x_size', '__num_hitters', '__smallest'])
+
     def __init__(self, num_hitters=100, width=None, depth=None,
                  confidence=None, error_rate=None, filepath=None,
                  hash_function=None):
@@ -549,6 +563,8 @@ def clear(self):
 class StreamThreshold(CountMinSketch):
     ''' keep track of those elements over a certain threshold '''
 
+    __slots__ = ['__threshold', '__meets_threshold']
+
     def __init__(self, threshold=100, width=None, depth=None,
                  confidence=None, error_rate=None, filepath=None,
                  hash_function=None):
diff --git a/probables/cuckoo/__init__.py b/probables/cuckoo/__init__.py
index c77757a..9ef6bfd 100644
--- a/probables/cuckoo/__init__.py
+++ b/probables/cuckoo/__init__.py
@@ -3,3 +3,5 @@
 
 from . cuckoo import (CuckooFilter)
 from . countingcuckoo import (CountingCuckooFilter)
+
+__all__ = ['CuckooFilter', 'CountingCuckooFilter']
diff --git a/probables/cuckoo/countingcuckoo.py b/probables/cuckoo/countingcuckoo.py
index e7fbc6f..a77056a 100644
--- a/probables/cuckoo/countingcuckoo.py
+++ b/probables/cuckoo/countingcuckoo.py
@@ -27,6 +27,10 @@ class CountingCuckooFilter(CuckooFilter):
             filename (str): The path to the file to load or None if no file
         Returns:
             CountingCuckooFilter: A Cuckoo Filter object '''
+
+    __slots__ = CuckooFilter.__slots__
+    __slots__.extend(['__unique_elements'])
+
     def __init__(self, capacity=10000, bucket_size=4, max_swaps=500,
                  expansion_rate=2, auto_expand=True, finger_size=4,
                  filepath=None, hash_function=None):
diff --git a/probables/cuckoo/cuckoo.py b/probables/cuckoo/cuckoo.py
index d05a3bd..7fd2376 100644
--- a/probables/cuckoo/cuckoo.py
+++ b/probables/cuckoo/cuckoo.py
@@ -32,6 +32,13 @@ class CuckooFilter(object):
             `hf(key)`
         Returns:
             CuckooFilter: A Cuckoo Filter object '''
+
+    __slots__ = [
+        '_bucket_size', '_cuckoo_capacity', '__max_cuckoo_swaps', '__expansion_rate',
+        '__auto_expand', '__fingerprint_size', '__hash_func', '_inserted_elements',
+        '_buckets'
+    ]
+
     def __init__(self, capacity=10000, bucket_size=4, max_swaps=500,
                  expansion_rate=2, auto_expand=True, finger_size=4,
                  filepath=None, hash_function=None):
diff --git a/setup.cfg b/setup.cfg
index 3c6e79c..a793a6f 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -1,2 +1,8 @@
 [bdist_wheel]
 universal=1
+
+[pep8]
+max-line-length=120
+
+[flake8]
+max-line-length=120