diff --git a/ChangeLog.md b/ChangeLog.md
--- a/ChangeLog.md
+++ b/ChangeLog.md
@@ -1,5 +1,12 @@
 # Changelog for hasklepias
 
+## 0.4.3
+
+* Exports `Feature` constructor.
+* Adds `defineFEF2` function for creating a feature definition where the provided function returns a `Feature d` rather than just a `d`.
+* Generalizes `allPairs` from type `[a] -> [a] -> [(a, a)]` to `[a] -> [b] -> [(a, b)]`.
+* Reexports a few functions and types from `Data.Time.Calendar`. Also reexports `const` from `Data.Function`.
+
 ## 0.4.2
 
 * Updates `interval-algebra` to 0.8.0
diff --git a/hasklepias.cabal b/hasklepias.cabal
--- a/hasklepias.cabal
+++ b/hasklepias.cabal
@@ -1,6 +1,6 @@
 cabal-version:  2.2
 name:           hasklepias
-version:        0.4.2
+version:        0.4.3
 description:    Please see the README on GitHub at <https://github.com/novisci/asclepias#readme>
 homepage:       https://github.com/novisci/asclepias/#readme
 bug-reports:    https://github.com/novisci/asclepias/issues
@@ -47,7 +47,7 @@
     , flow == 1.0.22
     , interval-algebra == 0.8.0
     , text >=1.2.3
-    , time >=1.9
+    , time >=1.11
     , unordered-containers >=0.2.10
     , safe >= 0.3
     , vector >=0.12
@@ -79,7 +79,7 @@
     , hspec
     , interval-algebra == 0.8.0
     , text >=1.2.3
-    , time >=1.9
+    , time >=1.11
     , unordered-containers >=0.2.10
     , vector >=0.12
     , QuickCheck
@@ -104,7 +104,7 @@
     , text >=1.2.3
     , bytestring >=0.10
     , containers >=0.6.0
-    , time >=1.9
+    , time >=1.11
     , aeson >=1.4.0.0 && <2
     , unordered-containers >=0.2.10
     , vector >=0.12
diff --git a/src/Hasklepias/Functions.hs b/src/Hasklepias/Functions.hs
--- a/src/Hasklepias/Functions.hs
+++ b/src/Hasklepias/Functions.hs
@@ -129,7 +129,7 @@
 makePairedFilter fi i fc = filter (makePairPredicate fi i fc)
 
 -- | Generate all pair-wise combinations from two lists.
-allPairs :: [a] -> [a] -> [(a, a)]
+allPairs :: [a] -> [b] -> [(a, b)]
 allPairs = liftA2 (,)
 
 -- | Split an @Events a@ into a pair of @Events a@. The first element contains
diff --git a/src/Hasklepias/Reexports.hs b/src/Hasklepias/Reexports.hs
--- a/src/Hasklepias/Reexports.hs
+++ b/src/Hasklepias/Reexports.hs
@@ -33,7 +33,7 @@
                                             , (&&), not, (||)
                                             , bool
                                             , otherwise )
-import safe Data.Function                   ( (.), ($) )
+import safe Data.Function                   ( (.), ($), const )
 import safe Data.Functor                    ( fmap )
 import safe Data.Int                        ( Int )
 import safe Data.List                       ( all, map, filter, length, null )
@@ -49,6 +49,7 @@
                                               maybeToList )
 import safe Data.Ord                        ( Ord((>=), (<), (>), (<=))
                                             , max, min )
+import safe Data.Time.Calendar              ( Day, fromGregorian, MonthOfYear, Year )
 import safe Data.Text                       ( pack, Text )
 import safe Data.Tuple                      ( fst, snd, uncurry, curry )
 import safe Flow                            ( (!>), (.>), (<!), (<.), (<|), (|>) )
diff --git a/src/Hasklepias/Types/Feature.hs b/src/Hasklepias/Types/Feature.hs
--- a/src/Hasklepias/Types/Feature.hs
+++ b/src/Hasklepias/Types/Feature.hs
@@ -15,13 +15,13 @@
 
 module Hasklepias.Types.Feature(
     -- * Types
-      Feature
-    , getFeature
+      Feature(..)
     , MissingReason(..)
     , FeatureDefinition(..)
     , applyEF
     , defineEF
     , defineFEF
+    , defineFEF2
     , applyFEF
     , featureR
     , featureL
@@ -106,6 +106,19 @@
   case feat of
     (Left _)  -> featureL r
     (Right x) -> featureR (g x es)
+  )
+
+defineFEF2 :: (Intervallic Interval a) =>
+             MissingReason
+          -- ^ The reason if the input 'Feature' is a 'Left'.
+          -> (e -> Events a -> Feature d)
+          -- ^ A function that tranforms the data of a 'Right' input 'Feature'
+          --   and a collection of events into the desired type.
+          -> FeatureDefinition e a d
+defineFEF2 r g = FEF (\(Feature feat) es ->
+  case feat of
+    (Left _)  -> featureL r
+    (Right x) -> g x es
   )
 
 -- | Extract a 'FEF' FeatureDefinition