diff --git a/converter_rayon/src/utils/argument_parser.rs b/converter_rayon/src/utils/argument_parser.rs
index b6eb725..468977d 100644
--- a/converter_rayon/src/utils/argument_parser.rs
+++ b/converter_rayon/src/utils/argument_parser.rs
@@ -6,7 +6,7 @@ pub struct CliArgs {
     #[arg(short, long)]
     pub table: String,
 
-    #[arg(short, long, default_value_t = String::new())]
+    #[arg(short, long, default_value_t = String::from("lat-"))]
     pub prefix: String,
 
     #[arg(short, long, default_value_t = String::new())]
diff --git a/converter_tokio/src/utils/argument_parser.rs b/converter_tokio/src/utils/argument_parser.rs
index b6eb725..468977d 100644
--- a/converter_tokio/src/utils/argument_parser.rs
+++ b/converter_tokio/src/utils/argument_parser.rs
@@ -6,7 +6,7 @@ pub struct CliArgs {
     #[arg(short, long)]
     pub table: String,
 
-    #[arg(short, long, default_value_t = String::new())]
+    #[arg(short, long, default_value_t = String::from("lat-"))]
     pub prefix: String,
 
     #[arg(short, long, default_value_t = String::new())]