For any lugnuts, NEVER buy aluminum. The threads will strip off with the first or second use. Aluminum lugnuts also tend to loosen over time caused by the heating and cooling cycle of the wheels.
im cureently using the red metal lugnuts elevo brand which i bought from concorde.. at first it was pleasing to look at.. but after some the colored coating peels off exposing chrome like coating with sign of rust build up at the endings.. its a so-so for a cheapo lugnuts in the market today..buy the steel one