Tea Infusers/ Tea Balls

What is a tea infuser? A Tea Infuser is an accompaniment to the teacup or teapot, usually ball or spoon-shaped, with a perforated or mesh style container to allow water to flow through. How do I use a tea ball or infuser?  Put one teaspoon of dry tea leaves, per standard cup (250ml), into the infuser. Place the infuser in a cup and add freshly boiled hot water.