I'm one of very few using one of them here, 8 ok years now. I don't think I have seen them in stores since that year. The outer coil is about 21 mm ( metal + plastic) , but the cable is 9 or 8 mm I think. They look like more trouble than they are. It's long enough to go around a light pole. They are a bulky nuisance to carry around. Probably lighter than a 1/2 " u-lock.