I have tried another stainless steel pour-over coffee filters with built-in holder (like a ring under it) that fits directly into the mug/ glass and i am satisfied with it. So at first i was quite skeptical when i saw the shape of this coffee filter, until i tried it. It exceeds my expectation, because it is not only fit for a glass/ mug, but it can also be used on any other container that has narrower opening. So, basically more 'options' available without the rings installed under it.This stainless steel pour over coffee is great for anyone that only needs a cup or two coffee every day, and doesn't want bulky coffee machine takes up space counter. It is very straight forward and simple to use, to clean and to store. I just hand wash this coffee filter under cold running water, and using brush to remove any grind left. And moreover, this really saves the environment by reducing the usage of the paper filters.This is my honest opinion in exchange of an opportunity to try and review this product. Thank you.