Just pour cold milk (skim, 1 or 2% fat) in the glass jug and move the plunger up and down a few times. You’re rewarded with the most luscious foam imaginable. If you like your foam hot, just put the glass jug with the foamed milk into the microwave for about 30 seconds.
The jug is made from borosilicate glass, which is sturdy and light at the same time and doesn’t cloud – even after years of dishwasher use. The plunger is made from stainless steel and plastic.