diff --git a/facho/model/__init__.py b/facho/model/__init__.py
index 0c2f73c..59b8d55 100644
--- a/facho/model/__init__.py
+++ b/facho/model/__init__.py
@@ -42,7 +42,7 @@ class ModelBase(object, metaclass=ModelMeta):
             if isinstance(v, fields.Field):
                 obj._order_fields.append(key)
 
-            if isinstance(v, fields.Attribute) or isinstance(v, fields.Many2One) or isinstance(v, fields.Function):
+            if isinstance(v, fields.Attribute) or isinstance(v, fields.Many2One) or isinstance(v, fields.Function) or isinstance(v, fields.Amount):
                 if hasattr(v, 'default') and v.default is not None:
                     setattr(obj, key, v.default)
                 
diff --git a/facho/model/fields/__init__.py b/facho/model/fields/__init__.py
index 6e9408d..081f195 100644
--- a/facho/model/fields/__init__.py
+++ b/facho/model/fields/__init__.py
@@ -4,8 +4,9 @@ from .one2many import One2Many
 from .function import Function
 from .virtual import Virtual
 from .field import Field
+from .amount import Amount
 
-__all__ = [Attribute, One2Many, Many2One, Virtual, Field]
+__all__ = [Attribute, One2Many, Many2One, Virtual, Field, Amount]
 
 def on_change(fields):
     from functools import wraps
diff --git a/tests/test_model.py b/tests/test_model.py
index f6ae1ee..7104920 100644
--- a/tests/test_model.py
+++ b/tests/test_model.py
@@ -489,3 +489,20 @@ def test_model_attributes_order():
 
     assert '<Invoice><Line1 quantity="1"/><Line2 quantity="2"/><Line3 quantity="3"/></Invoice>' == invoice.to_xml()
 
+
+def test_field_amount():
+    class Line(facho.model.Model):
+        __name__ = 'Line'
+
+        amount = fields.Amount(name='Amount', precision=0)
+        amount_as_attribute = fields.Attribute('amount')
+
+        @fields.on_change(['amount'])
+        def on_amount(self, name, value):
+            self.amount_as_attribute = self.amount
+
+    line = Line()
+    line.amount = 33
+
+    assert '<Line amount="33"/>' == line.to_xml()
+        
diff --git a/tests/test_model_invoice.py b/tests/test_model_invoice.py
index 6472fd0..79d3604 100644
--- a/tests/test_model_invoice.py
+++ b/tests/test_model_invoice.py
@@ -34,7 +34,7 @@ def _test_simple_invoice_cufe():
     invoice.customer.party.id = '800199436'
 
     line = invoice.lines.create()
-    line.quantity = form.Quantity(1, '94')
-    line.price = form.Amount(1_500_000)
+    line.quantity = 1
+    line.price = 1_500_000
     subtotal = line.taxtotal.subtotals.create()
     subtotal.percent = 19.0