A Simmer Cat has one row of holes. A big advantage is it can hold more fuel and burn longer/slower, if that is your desire. Also, I found that if you us cut some short pieces of wire, bent in a "U" shape and drape over the rim of the stove, so that there is about a 1 mm gap between the stove and the pot, the heat output of the simmercat is greatly increased to be almost that of a supercat, giving nice dual use. Or just bring one of each as they cost and weigh very little.