The NanoMag is an itsy-bitsy, lean, high-energy, window-cleaning apparatus. Its patent-pending design provides flexibility and a slender profile that slips safely between polyps and viewing windows. It's got the umph needed for cleaning glass up to 3/8" thick. The NanoMag also glides across the curved surfaces of fish bowls, wiping off algal films with ease, and it's so much fun to use, you just might have to take turns! Scrubber pad measures 1" x 1" x 1/8" thick. External magnet measures 1½" diameter.