diff --git a/aqt/jax/v2/config.py b/aqt/jax/v2/config.py
index 1bde8dd8..da6c1832 100644
--- a/aqt/jax/v2/config.py
+++ b/aqt/jax/v2/config.py
@@ -216,7 +216,7 @@ def _set_noise_fn(
 
 
 def set_constant_calibration(
-    cfg: DotGeneral, bound: float = 1.0, bias: float | None = None
+    cfg: DotGeneral, bound: Union[jnp.ndarray, float], bias: float | None = None
 ):
   """Sets the static bound for calibration."""
   calibration_cls = functools.partial(