Nope, this is not a furnace filters. It is a Icon Solo LED Pen Light.
You can easily ignore these things nowadays for some lazy reasons that includes your keyboard, computer and printer. But having this handy won’t really hurt you specially when it comes with pre-installed led-light. This Icon Solo LED Pen Light has a dual output LED pen light that beams at 16 lumens and 2 lumens that you can easily toggle depending on your preference. It is also waterproof so it’s not really a problem when you’re needing it underwater for some reason. It also comes with AAA batteries that could give around 75 hours of total usage. And hey, did I forgot to mention that it can be used on paper as well? Its a pen afterall.