diff --git a/rds-postgres/main.tf b/rds-postgres/main.tf
index 49bf86e..7d2efd7 100644
--- a/rds-postgres/main.tf
+++ b/rds-postgres/main.tf
@@ -105,7 +105,7 @@ resource "aws_security_group" "this_security_group" {
       from_port       = 0
       to_port         = 0
       protocol        = -1
-      security_groups = [local.ingress_sg]
+      security_groups = local.ingress_sg
     }
   }
 
@@ -143,7 +143,7 @@ resource "aws_security_group" "this_security_group" {
       from_port       = 0
       to_port         = 0
       protocol        = -1
-      security_groups = [local.egress_sg]
+      security_groups = local.egress_sg
     }
   }