I was skeptical, but this product is absolutely amazing. Once I poured it down my shower drain, you could almost hear the water draining all the way to the streets -- it made the drain WIDE OPEN. The bonus with this product is that is it not caustic and does not damage or discolor any "metal" drain covers in your sinks or showers. I previously was using Liquid Lightning drain opener, which worked great but it is so caustic that if a drop hits your skin while you are pouring, it leaves a burn mark -- not to mention it totally takes the finish/color off of your drain covering. Enzymatic Drain Cleaner is a must buy!