The genuine Nu-Calgon 4185-03 is a 12 ct. Tube of Gel Tabs - 3 Ton Tabs and is best used for cleaning condensate drain pans and lines. Gel Tabs - 3 Ton Tabs are non-corrosive to metals and eliminates foul and musty odors. The Nu-Calgon 4185-03 completely dissolves delivering up to 3 months of protection. Nu-Calgon Gel Tabs - 3 Ton Tabs has a unique “gel” formulation encompassing breakthrough technology for keeping drain pans clean and free from plugging. Nu-Calgon, the brand you trust, provides quality chemicals and specialty products for professional use only in the air conditioning, refrigeration and heating markets.