diff --git a/tests/test_add_connections.py b/tests/test_add_connections.py
index 454bf5d..5fa8f7f 100644
--- a/tests/test_add_connections.py
+++ b/tests/test_add_connections.py
@@ -44,6 +44,7 @@ def test_AddLists(use_graph):
             outs = AddOne(lst1.outs + lst2.outs)
 
         assert isinstance(outs.value, CombinedConnections)
+        assert len(outs.value) == 2
         assert len(outs.value.connections) == 2
         assert outs.value.connections[0].instance is lst1
         assert outs.value.connections[0].attribute == "outs"
diff --git a/znflow/base.py b/znflow/base.py
index d69446d..80e83f4 100644
--- a/znflow/base.py
+++ b/znflow/base.py
@@ -331,6 +331,9 @@ def __radd__(self, other):
     def __getitem__(self, item):
         return dataclasses.replace(self, item=item)
 
+    def __len__(self) -> int:
+        return len(self.connections)
+
     def __iter__(self):
         raise TypeError(f"Can not iterate over {self}.")