 500 grams and six centimetres wide. And how big should we make our shelf? Three metres? Perfect. So if we've got three metres worth of six centimetre modems, that's 50 modems per shelf. There are 22,000 shelves or pops. So that's 1,100,000 modems or 550,000 kilograms of pops. But we need to add in all the actual modems people have in their homes, right?