The large bag is 30 inches deep at the sides and comfortably accommodates fish up to 20 pounds. The magnum bag has 36 inch sides and can hold any salmon you are likely to catch. My boat has 30 inch sides so the smaller bag is ideal for releasing fish 20# or less. They lay perfectly flat on the surface submerged in a few inches of water while I'm dealing with them. The bigger bag obviously works better for bigger fish.