This extra fine 18/8 stainless steel food grade tea infuser fits almost any mug with it's 5-inch height and 3-inch width. The extra fine mesh catches loose leaves and sediment easily and prevents tea particles from escaping into your steeped cup of tea. Simply place directly in your mug of heated water, add tea leaves, cover with the included lid, steep for desired amount of time, remove and allow to drain over the mug, and then use the lid as a drip plate.