I had never seen them before either :) I never use them because I have a digitial scale and I was hoping they would help someone out!! It's all about Listia and making people happy :) Hope they come in handy for someone!!
You place the first scale on a flat surface and if the point touches the surface, the item is heavier than the weight indicated. You stack the next scale on top and repeat the process, and if necessary again with a 3rd scale. it will weigh up to 6 lbs. Hope that helps :)