Stainless Steel, Ultra-fine mesh, fine filtering, and durable. You can infuse Tea, Herbs, Spices, or others. 
Suitable for most mugs and cups, and also easy to use and clean. This product is reusable, and produce less trash than store-brought disposable tea bags.
To use: Slightly push open the mesh ball, and insert the herb or tea, and then release slowly to tightly seal it.