These are vintage Campagnolo Lug nuts for Alfa Romeo and other Italian cars. They are M12X1.5 mm, and are 19mm socket size. Inside depth is about 250cm. There are 8 left-hand thread nuts for the left side and 8 right-handers for the right side wheels. These were on my concourse award winning 1960 Giulietta Spider Veloce. I also have a right hand set on NOS never used set of four for sale. Vintage Campagnolo Lug nuts Alfa Romeo, Giulietta, Giulia, Italian, Fiat | eBay