diff --git a/src/aeso_aci.erl b/src/aeso_aci.erl
index 5f9fd25..2edba2c 100644
--- a/src/aeso_aci.erl
+++ b/src/aeso_aci.erl
@@ -266,7 +266,7 @@ decode_type(#{tuple := Ets}) ->
     Ts = decode_types(Ets),
     case Ts of
         [] -> ["unit"];
-        _ -> ["(", $(,lists:join(" * ", Ts),$), ")"]
+        _ -> [$(,lists:join(" * ", Ts),$)]
     end;
 decode_type(#{record := Efs}) ->
     Fs = decode_fields(Efs),