I purchased four of these Craftsman six-inch clamps at K-mart. They are the exact same model as at Sears. I pleased with the clamping power of these clamps. I tried several at the store to make sure I was getting clamps which didn't appear to slip when tightened. These have a really smooth action when adjusting. Interestingly, these clamps are not made in China, rather in Eastern Europe. They have a one-year warranty rather than the lifetime warranty available on some Craftsman tools.
I ordered two of these from the website after ordering some 24 inch versions of the same and being pretty happy with those. They work really well. I'd recommend them to anyone.
This clamp works great and can be used with one hand while the other holds your project. I wish I had more of them because usually I leave them some in a place other than where I now need them.
Realized that they were made in Slovakia, not China. Check the mating of the jaws and the action to open and close. Some of the ones in the store would not ratchet properly. The ones I chose worked well and did the job.