Promising review: "This is the best thing you never knew you needed. I own a digital clock with the numbers displayed in red LED light, and every night I've blocked the light with a cover so it doesn't shine in my eyes as I sleep. Silly I know, but I like my room pitch black and cave-like. On a whim, I bought this product. OH MY GOD! Game-changer!! For the first night EVER I didn't have to cover the clock display before I went to bed!! I had no idea how big a difference this little dimmer could make, but I'm more than pleased with the result. I can still see the time display just fine, but now my room is a happy cave! Some commenters argue you could get the same effect using electrical tape, regular tape covered in sharpie, etc, but true to the name of these products if you're looking for something to DIM, then this is for you. Also, the product is easy to remove and doesn't leave a sticky residue at all, which can't be said for most tapes. I did notice a slight lag in response when I covered my TV LED sensor, so if you're trying to block something that actually senses inputs I would maybe not suggest this. Other than that, excellent product!" —Amazon Customer
Get a sheet of over 100 dimming stickers (in multiple sizes and shapes) from Amazon for $6.49.