Wera39s stainless steel tools are industrial strength made from the highest quality materials combined with a special vacuum ice hardening process the use of stainless tools is essential in eliminating the risk of stainless steel fasteners discolouring and rusting this happens after normal ferrous metal tools are used with stainless steel screws and cross contamination occurs this set is specially developed for mobility flexibility and versatility offering both power and hand screwdrivin