Useful information about Bialetti Moka Express Diamond Cups: 3 or 6Material: Aluminum Dishwasher: NoColor: Antracit grey micro-glitter coatingGas, ceramic and electricBialettiAlfonso Bialetti also called " the little man with moustachet " invented espresso jug back in 1933. Bialetti has since then been a strong brand worldwide and symbolizes Italian design and quality.Bialetti is best known for their expresso pot, which is a known symbol of Italian culture. The rest of the world is being brought to the Italian wave and luckily they would like to share the delicious taste.