Clingers Only is easy to fill and clean. Protects the birds we love from disease. Entire lid comes off to fill from top and easily locks back into place. Very small port on others which swivel open to fill (in snow and ice these freeze solid). Large Capacity Holds 2-3 times more than other small bird feeders which often run out quickly 3.5 to 4 cups of seed. A special feeder for Chickadees.