Zip-It Drain Cleaning tool for several years now. Having two girls with long hair, I found the drain in their bathroom backing up to the the point where the bathtub wouldn't even drain. Because of the way the drain is made (the plug screws in and there are four small openings around the center where it screws in), there is a very small opening and a normal drain snake wouldn't fit. Even if it did, I'm afraid it would just push the hair clog further down the drain. I didn't want to use chemicals if I didn't have to. One day, while at Lowe's I found this little piece of plastic with hooks on it. It's an extremely simple device. It goes in, pushing through the hair, and when it comes out, the barbs grip the hair pulling it out. The device is disposable. But, I'm cheap. I'll use them several times before throwing them out even though they're less than $3.00 each. No chemicals to harm the environment, your fixtures or your pipes.
Here's a picture of the clog I just pulled out. This is only about two months worth of hair.