Porta-Pak is the top-selling portion-control deodorizer in the world, manufactured by the Walex, the odor control experts. The slide-zipper bag contains ten water-soluble drop-in packets. The lavender-scented water-soluble packet controls odors, breaks down waste and paper, and lubricates valves and seals. Porta-Paks premium formula works even in the heat of summer. The high-performance packet is formaldehyde-free. To use Porta-Pak, drop one packet in the toilet and flush to add water. One Porta-Pak provides week-long odor control for up to a 40-gallon black tank.