I can't remember for sure, but I think they were ruffwear boots that I got for my dog. They have rubber tread on the bottom. He only has 3 legs so I wanted something that would help him grip a bit better on the ice. I will find out what they were for sure though.
Edit: http://www.amazon.com/Ruffwear-Bark-Boots-Grip-Footwear/dp/B000N3VW4M/ref=sr_1_fed0_3?ie=UTF8&qid=1353525997&sr=8-3&keywords=ruffwear+boots. I got them from a local store, and they were a bit cheaper. Shouldn't wear out as fast as some of the other ones either.