Portafilter
What is portafilter in coffee?
A portafilter is the handle-and-holder you fill with ground coffee and lock into an espresso machine. It holds a metal filter basket; you dose and tamp the coffee into the basket, lock the portafilter into the machine's group head, and the espresso pours out through its spout underneath.
Single and double baskets hold different amounts of coffee, so use the basket that matches your dose. After each shot, knock out the used coffee and rinse the basket before the next one. See the espresso guide.