diff --git a/.travis.yml b/.travis.yml
index 6aef1f7f..c64ba7f2 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -4,7 +4,7 @@ python:
 
 # Setup anaconda
 before_install:
-  - if [ ${TRAVIS_PYTHON_VERSION:0:1} == "2" ]; then wget http://repo.continuum.io/miniconda/Miniconda-3.3.0-Linux-x86_64.sh -O miniconda.sh; else wget http://repo.continuum.io/miniconda/Miniconda3-3.3.0-Linux-x86_64.sh -O miniconda.sh; fi
+  - if [ ${TRAVIS_PYTHON_VERSION:0:1} == "2" ]; then wget http://repo.continuum.io/miniconda/Miniconda-3.8.3-Linux-x86_64.sh -O miniconda.sh; else wget http://repo.continuum.io/miniconda/Miniconda3-3.8.3-Linux-x86_64.sh -O miniconda.sh; fi
   - chmod +x miniconda.sh
   - ./miniconda.sh -b
   - export PATH=/home/travis/anaconda/bin:/home/travis/miniconda/bin:$PATH
@@ -17,7 +17,7 @@ before_install:
 install:
   - conda install --yes pip python=$TRAVIS_PYTHON_VERSION numpy scipy matplotlib cython
   - pip install nose-cov python-coveralls
-  # Remove this when SimPEG is on pip
+    # Remove this when SimPEG is on pip
   - git clone https://github.com/simpeg/simpeg.git
   - cd simpeg/
   - python setup.py install
@@ -35,3 +35,4 @@ notifications:
   email:
     - rowanc1@gmail.com
     - sgkang09@gmail.com
+    - lindseyheagy@gmail.com
diff --git a/simpegEM/Base.py b/simpegEM/Base.py
index da7e4a86..e2298ed0 100644
--- a/simpegEM/Base.py
+++ b/simpegEM/Base.py
@@ -17,15 +17,31 @@ class BaseEMProblem(Problem.BaseProblem):
 
     verbose = False
 
+
+    ####################################################
+    # Mu Model
+    ####################################################
+    @property
+    def mu(self):
+        if getattr(self, '_mu', None) is None:
+            self._mu = mu_0
+        return self._mu
+    @mu.setter
+    def mu(self, value):
+        if getattr(self, '_MfMui', None) is not None:
+            del self._MfMui
+        self._mu = value
+        
+
+
     ####################################################
     # Mass Matrices
     ####################################################
 
     @property
     def MfMui(self):
-        #TODO: assuming constant mu
         if getattr(self, '_MfMui', None) is None:
-            self._MfMui = self.mesh.getFaceInnerProduct(1/mu_0)
+            self._MfMui = self.mesh.getFaceInnerProduct(1/self.mu)
         return self._MfMui
 
     @property
diff --git a/simpegEM/Tests/test_FDEM.py b/simpegEM/Tests/test_FDEM.py
index a76ad539..e1d8f1c5 100644
--- a/simpegEM/Tests/test_FDEM.py
+++ b/simpegEM/Tests/test_FDEM.py
@@ -2,9 +2,12 @@ import unittest
 from SimPEG import *
 import simpegEM as EM
 import sys
+from scipy.constants import mu_0
 
 TOL = 1e-4
 CONDUCTIVITY = 1e3
+MU = mu_0
+addrandoms = True 
 
 def getProblem(fdemType, comp):
     cs = 5.
@@ -44,7 +47,14 @@ def adjointTest(fdemType, comp):
     prb = getProblem(fdemType, comp)
     print 'Adjoint %s formulation - %s' % (fdemType, comp)
 
-    m = np.log(np.ones(prb.mesh.nC)*CONDUCTIVITY)
+    m  = np.log(np.ones(prb.mesh.nC)*CONDUCTIVITY)
+    mu = np.log(np.ones(prb.mesh.nC)*MU)
+
+    if addrandoms is True:
+        m  = m + np.random.randn(prb.mesh.nC)*CONDUCTIVITY*1e-3 
+        mu = mu + np.random.randn(prb.mesh.nC)*MU*1e-3
+
+    prb.mu = mu 
     survey = prb.survey
 
     v = np.random.rand(survey.nD)
@@ -61,6 +71,13 @@ def derivTest(fdemType, comp):
     prb = getProblem(fdemType, comp)
     print '%s formulation - %s' % (fdemType, comp)
     x0 = np.log(np.ones(prb.mesh.nC)*CONDUCTIVITY)
+    mu = np.log(np.ones(prb.mesh.nC)*MU)
+
+    if addrandoms is True:
+        x0  = x0 + np.random.randn(prb.mesh.nC)*CONDUCTIVITY*1e-3 
+        mu = mu + np.random.randn(prb.mesh.nC)*MU*1e-3
+
+    prb.mu = mu 
     survey = prb.survey
     def fun(x):
         return survey.dpred(x), lambda x: prb.Jvec(x0, x)