Steam Wand
Most espresso coffee makers whether steam boiler or pump enabled, usually come with a built in steam wand, for frothing milk to make a creamy cappuccino. The steam wand is a small solid metal pipe about 5 centimeters in length and is part of the machine design, usually sticking out from one end near the coffee shower head or group head.
The steam wand is internally connected to the boiler by a flexible pipe and forms a path for the flow of steam generated in the boiler. A valve connected between the wand and the flexible pipe provides the possibility to regulate the flow of steam. This valve is mechanical and can be controlled by hand, usually a simple knob built on the side of the machine.