The BlueSpot 4 PCE Multi Drill Set is manufactured from HSS4241 hardened high speed steel for increased strength and durability. The set is ideal for use with power tools and is suitable for drilling in wood, plastics, steel, aluminium and other non-ferrous metals. For best results, use with sheet materials below 10mm. Not suitable for use with stainless steel. The set is supplied in a plastic box for easy storage and transportation.