The Ultra Powrpak for portable restrooms and holding tanks from CPACEX is formulated to offer continuous odor control and fragrance for seven days in extreme temperatures and conditions, or for special events where overuse may occur. The packets effervesce to dissolve quickly and disperse evenly throughout the holding tank. They are available in five sizes to fit specific applications and climates. The packs are biodegradable and contain nonstaining blue dye. 800/974-7383; www.cpacex.com.