TRUSTED BRAND: Drano Max Gel Drain Clog Remover is the #1 Selling Gel Drain Cleaner*. Avoid spending money on a plumber and use Drano. FAST-ACTING: Starts working 7 minutes. For best results, pour half the bottle (21 oz) slowly over drain. For extremely slow-running drains or complete clogs, use 42 oz. Allow Drano to sit for 15-30 minutes and flush with hot water. Repeat if necessary. REMOVES CLOGS: Pours through standing water straight to the clog. Use Drano whenever major clogs occur. SAFE ON PIPES: Safe for bathroom and kitchen sinks. Drano Max Gel includes an ingredient to protect pipes from corrosion over time without compromising the efficacy of the clog remover. GREAT FOR PREVENTING CLOGS: Act on slow running drains before the clog forms. Cheaper than a plumber.