Saim Daily Double II Battery-Operated Automatic Fish Feeder Daily Double II automatic fish feeder Large capacity food drum with adjustable setting Two kinds if time setting: 12 hours feed and 24 hours feed.(Short press the "SET" button and wait for 3 seconds to set the time). Or feed the fish when needed even you set the time: Long press for 3 seconds to feed your fish. It fits on most aquariums and includes a universal installation clamp and suction to make set-up easier for you.