However, many wouldn't know what the white circle with two crossed lines signifies ... An empty triangle means the item can be bleached, a crossed-out triangle means it shouldn't be bleached ...

are fairly easy to work out, showing the owner the maximum temperature the item should be washed at. But many people would not be able to tell you what the white circle, with two crossed lines ...

Almost all digital cameras with interchangeable optics display a symbol that looks like a crossed-out circle. This symbol isn't a contemporary feature but was already seen on film devices.