diff --git a/reduction_tools/cat_lst.py b/reduction_tools/cat_lst.py
index 428a7a1..b1b8118 100644
--- a/reduction_tools/cat_lst.py
+++ b/reduction_tools/cat_lst.py
@@ -144,7 +144,7 @@ if __name__ == "__main__":
     parser.add_argument(
         "-p",
         "--pgroup",
-        help="pgroup the data are collected in",
+        help="pgroup the data are collected in - in form p#####",
         type=str
         )
     parser.add_argument(
@@ -157,7 +157,7 @@ if __name__ == "__main__":
     parser.add_argument(
         "-o",
         "--output",
-        help="name of output file",
+        help="name of output file - script will add .lst",
         type=str,
         )
     args = parser.parse_args()
@@ -176,4 +176,4 @@ if __name__ == "__main__":
     print( "appending {0} lst files from runs {1}".format( args.label, run_lst ) )
     # run main
     main( run_lst, args.endstation, args.label, args.pgroup, args.output )
-    print( "done" )
\ No newline at end of file
+    print( "done" )