Mosalogic Indoor Sticky Glue Cards Double-Sided Flies Gnats Trap Stick,10 Count

This bug attractant works to attract and kill gnats. It emits a blue light which draws the bugs to the sticky card where they land on it and can't get off. I replace the card when it has a lot of gnats on it. If the device doesn't work, I put a little container of apple cider vinegar (covered with Handi-wrap with a few holes on the top) on a counter and the gnats crawl inside and drown. This works really well, but when the container is full of gnats, you have to wash out the container and refill it. It's a little messy, but it works well.