diff --git a/lisainstrument/containers.py b/lisainstrument/containers.py
index d26b72091e1af4b55f51bf4f9f18589bf9344079..19856e5b6355b8263fc2ce32abbe66fef614bc03 100644
--- a/lisainstrument/containers.py
+++ b/lisainstrument/containers.py
@@ -31,7 +31,7 @@ class ForEachObject(abc.ABC):
             self.dict = {mosa: values[mosa] for mosa in self.indices()}
         elif callable(values):
             if concurrent:
-                with ThreadPoolExecutor() as executor:
+                with ThreadPoolExecutor(max_workers=3) as executor:
                     indices = self.indices()
                     computed_values = executor.map(values, indices)
                     self.dict = dict(zip(indices, computed_values))