Professional Drain Opener 1-Gallon NOTE: IN STORE PICKUP ONLY. NOT AVAILABLE FOR SHIPPING. A concentrated sulfuric acid designed to unclog and unstop even the most stubborn blockages while providing the maximum safety possible Opens sinks, floor drains, grease traps, and septic tanks Dissolves grease, food residue, paper, hair, soap, tobacco, and sanitary napkins. 1 gallon.