The can lid has been designed for standard size food cans. It has three different size of inner diameter--2.5 inch, 2.9 inch, 3.3 inch and stretches a bit is available. So one can lid can cover small,medium,and large pet food cans. In addition, these pet can covers are made of silicone which is very soft and flexible,allow them to fit snugly and grip the rim of the cans for giving a good seal. Not only keep pet food from going stale, but also control odors,keep refrigerator from smelling like dog and cat food!