These are great for the old faithful teapot that hasn't got with the “comes-with-infuser-basket” times. Fill the filter with the required amount of leaves, put in pot and pour hot water over bag to infuse. These are also great if you want a more controlled infusion; no more over infused leaves floating in the pot until the bitter end. They are unbleached and biodegradable too, so you can chuck them in the compost when you are done.