For ice fishing I haven't necessarily looked for just one brand or grams of thinsulate. Usually I look for rubber over the ankles, for slush and water on the ice. The next thing I look at is how thick the soles are. The farther away from the ice your feet are the better. The boots I found for my wife were a 30 dollar knock off brand, but the soles were almost 4 inches thick, she complains about the cold more than anybody, but now it's never her feet at least.