diff --git a/Metallicity_Stack_Commons/column_names.py b/Metallicity_Stack_Commons/column_names.py
index 3ad850f..66a6b3f 100644
--- a/Metallicity_Stack_Commons/column_names.py
+++ b/Metallicity_Stack_Commons/column_names.py
@@ -74,6 +74,14 @@ def line_fit_suffix_add(line_name0, line_type0):
 filename_dict['indv_bin_info'] = 'individual_bin_info.tbl'
 filename_dict['indv_derived_prop'] = 'individual_derived_properties.tbl'
 
+# numpy files
+npz_filename_dict = dict()
+npz_filename_dict['flux_pdf'] = 'flux_pdf.npz'
+npz_filename_dict['flux_errors'] = 'flux_errors.npz'
+npz_filename_dict['flux_peak'] = 'flux_peak.npz'
+npz_filename_dict['metal_errors'] = 'metal_errors.npz'
+npz_filename_dict['metal_peak'] = 'metal_peak.npz'
+
 
 def merge_column_names(*args):
     """