diff --git a/apps/wpmw/views.py b/apps/wpmw/views.py
index 7ee0ae8c..0d8b6d01 100644
--- a/apps/wpmw/views.py
+++ b/apps/wpmw/views.py
@@ -19,6 +19,7 @@ class WprViewSet(CustomListModelMixin, CustomGenericViewSet):
     filterset_fields = {
         "mb": ["exact", "isnull"],
         "wm": ["exact", "isnull"],
+        "material__process": ["exact"],
         "state": ["exact"],
         "defects": ["exact"]
     }
@@ -28,5 +29,8 @@ class WprViewSet(CustomListModelMixin, CustomGenericViewSet):
 
     def filter_queryset(self, queryset):
         qs = super().filter_queryset(queryset)
-        qs.exclude(mb=None, wm=None)
+        if "mb__isnull" in self.request.query_params or "wm__isnull" in self.request.query_params:
+            pass
+        else:
+            qs.exclude(mb=None, wm=None)
         return qs
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