diff --git a/basenji/seqnn.py b/basenji/seqnn.py
index 11f57dd..f8b3d35 100644
--- a/basenji/seqnn.py
+++ b/basenji/seqnn.py
@@ -187,7 +187,7 @@ def build_model(self, save_reprs=True):
       self.model_strides.append(1)
       for layer in self.model.layers:
         if hasattr(layer, 'strides') or hasattr(layer, 'size'):
-          stride_factor = layer.input_shape[1] / layer.output_shape[1]
+          stride_factor = layer.input.shape[1] / layer.output.shape[1]
           self.model_strides[-1] *= stride_factor
       self.model_strides[-1] = int(self.model_strides[-1])