diff --git a/doc/sphinx/src/using-eos.rst b/doc/sphinx/src/using-eos.rst
index 7f1d9758637..325d3989370 100644
--- a/doc/sphinx/src/using-eos.rst
+++ b/doc/sphinx/src/using-eos.rst
@@ -104,21 +104,6 @@ Similarly the method
 prints relevant parameters that the EOS object was created with, such
 as the Gruneisen coefficient and specific heat for an ideal gas model.
 
-If you would like to create your own custom variant with additional
-models (or a subset of models), you may do so by using the
-``eos_variant`` class. For example,
-
-.. code-block:: cpp
-
-  #include <singularity-eos/eos.hpp>
-  using namespace singularity;
-  
-  using MyEOS_t = eos_variant<IdealGas, Gruneisen>;
-
-This will create a new type, ``MyEOS_t`` which contains only the
-``IdealGas`` and ``Gruneisen`` classes. (All of these live under the
-``singularity`` namespace.)
-
 Reference Semantics and ``GetOnDevice``
 -----------------------------------------
 
@@ -488,11 +473,18 @@ currently:
 * ``thermalqs::temperature``
 * ``thermalqs::specific_heat``
 * ``thermalqs::bulk_modulus``
+* ``thermalqs::lambda``
 * ``thermalqs::all_values``
 
 however, most EOS models only specify that they prefer density and
 temperature or density and specific internal energy.
 
+.. note::
+
+   The ``thermalqs::lambda`` flag is a bit special. It specifies that
+   eos-specific operations are to be performed on the additional
+   quantities passed in through the ``lambda`` variable.
+
 .. _eos builder section:
 
 EOS Builder
diff --git a/python/module.cpp b/python/module.cpp
index 81db516a72a..218cd3ef784 100644
--- a/python/module.cpp
+++ b/python/module.cpp
@@ -141,6 +141,7 @@ PYBIND11_MODULE(singularity_eos, m) {
   thermalqs.attr("temperature") = pybind11::int_(thermalqs::temperature);
   thermalqs.attr("specific_heat") = pybind11::int_(thermalqs::specific_heat);
   thermalqs.attr("bulk_modulus") = pybind11::int_(thermalqs::bulk_modulus);
+  thermalqs.attr("lambda") = pybind11::int_(thermalqs::lambda);
   thermalqs.attr("all_values") = pybind11::int_(thermalqs::all_values);
 
   py::module eos_units = m.def_submodule("eos_units");
diff --git a/test/python_bindings.py b/test/python_bindings.py
index 5ae87f006dc..61a209c3383 100644
--- a/test/python_bindings.py
+++ b/test/python_bindings.py
@@ -61,7 +61,8 @@ def testConstants(self):
                                                thermalqs.pressure      |
                                                thermalqs.temperature   |
                                                thermalqs.specific_heat |
-                                               thermalqs.bulk_modulus)
+                                               thermalqs.bulk_modulus  |
+                                               thermalqs.lambda)
 
     def testIdealGas(self):
         eos = singularity_eos.IdealGas(1,1)