3 cup capacity / 4.5 oz (based on European 1.5 oz espresso cup) * Prime aluminum that ensures a blemish-free exterior with quality machined screw threads that ensure good pressure and a tight fit * Pressure valves have a stainless steel ball bearing and spring * The gaskets are made of 100% rubber * The thick, hollow ground base allows the Moka Express to be used on electric, gas or ceramic ranges