diff --git a/sqlalchemy_utils/types/range.py b/sqlalchemy_utils/types/range.py
index 62b932a..b19b5b3 100644
--- a/sqlalchemy_utils/types/range.py
+++ b/sqlalchemy_utils/types/range.py
@@ -194,9 +194,12 @@ class RangeType(types.TypeDecorator, ScalarCoercible):
 
     def process_result_value(self, value, dialect):
         if value:
-            return self.canonicalize_result_value(
-                self.interval_class(value)
-            )
+            if self.interval_class.step is not None:
+                return self.canonicalize_result_value(
+                    self.interval_class(value)
+                )
+            else:
+                return self.interval_class(value)
         return value
 
     def canonicalize_result_value(self, value):
@@ -289,7 +292,7 @@ class NumericRangeType(RangeType):
     impl = NUMRANGE
 
     def __init__(self, *args, **kwargs):
-        super(DateRangeType, self).__init__(*args, **kwargs)
+        super(NumericRangeType, self).__init__(*args, **kwargs)
         self.interval_class = intervals.DecimalInterval
 
 
@@ -297,5 +300,5 @@ class DateTimeRangeType(RangeType):
     impl = TSRANGE
 
     def __init__(self, *args, **kwargs):
-        super(DateRangeType, self).__init__(*args, **kwargs)
+        super(DateTimeRangeType, self).__init__(*args, **kwargs)
         self.interval_class = intervals.DateTimeInterval
diff --git a/tests/types/test_numeric_range.py b/tests/types/test_numeric_range.py
new file mode 100644
index 0000000..6458858
--- /dev/null
+++ b/tests/types/test_numeric_range.py
@@ -0,0 +1,80 @@
+from pytest import mark
+import sqlalchemy as sa
+intervals = None
+try:
+    import intervals
+except ImportError:
+    pass
+from tests import TestCase
+from infinity import inf
+from sqlalchemy_utils import NumericRangeType
+
+
+@mark.skipif('intervals is None')
+class NumericRangeTestCase(TestCase):
+    def create_models(self):
+        class Car(self.Base):
+            __tablename__ = 'car'
+            id = sa.Column(sa.Integer, primary_key=True)
+            price_range = sa.Column(NumericRangeType)
+
+        self.Car = Car
+
+    def create_car(self, number_range):
+        car = self.Car(
+            price_range=number_range
+        )
+
+        self.session.add(car)
+        self.session.commit()
+        return self.session.query(self.Car).first()
+
+    @mark.parametrize(
+        'number_range',
+        (
+            [1, 3],
+            '1 - 3',
+        )
+    )
+    def test_save_number_range(self, number_range):
+        car = self.create_car(number_range)
+        assert car.price_range.lower == 1
+        assert car.price_range.upper == 3
+
+    def test_infinite_upper_bound(self):
+        car = self.create_car([1, inf])
+        assert car.price_range.lower == 1
+        assert car.price_range.upper == inf
+
+    def test_infinite_lower_bound(self):
+        car = self.create_car([-inf, 1])
+        assert car.price_range.lower == -inf
+        assert car.price_range.upper == 1
+
+    def test_nullify_number_range(self):
+        car = self.Car(
+            price_range=intervals.IntInterval([1, 3])
+        )
+
+        self.session.add(car)
+        self.session.commit()
+
+        car = self.session.query(self.Car).first()
+        car.price_range = None
+        self.session.commit()
+
+        car = self.session.query(self.Car).first()
+        assert car.price_range is None
+
+    def test_string_coercion(self):
+        car = self.Car(price_range='[12, 18]')
+        assert isinstance(car.price_range, intervals.DecimalInterval)
+
+    def test_integer_coercion(self):
+        car = self.Car(price_range=15)
+        assert car.price_range.lower == 15
+        assert car.price_range.upper == 15
+
+
+class TestNumericRangeOnPostgres(NumericRangeTestCase):
+    dns = 'postgres://postgres@localhost/sqlalchemy_utils_test'