Double food container available - 100/210ml: The larger 210ml container holds 100g of fish food, while the smaller 100ml container holds 51g. Choose one depending on the time of year you're away, and it will have enough food to feed your fish while you're gone. Manual or automatic feeding: The automatic mode can be set to a convenient feeding schedule of every 8, 12, or 24 hours, helping you feed your fish automatically while you're on vacation or traveling. Additionally, the one-touch manual feeding doesn't interfere with the preset times. Two installation methods: For open tanks, attach the feeder to the glass side of the tank using the clips; for closed tanks, attach one side of the Velcro to the tank lid and the other side to the base of the feeder, securing the two sides together. (Note: When using Velcro, the surface must be cleaned before attaching it, and the feeder should be installed last.) Food Type Selection: This timed feeder can only be used for feeding dry food. It is ideal for pellets, granules, strips, and flakes of fish food. Please place it above the tank at a higher level to protect the food from moisture. Then, attach the aquarium lid, leaving only one hole. Place some aquatic plants in the hole and drop the food into it; the fish will come to eat it. Battery Operation (battery included): When cleaning the food container, simply remove it, rinse it thoroughly with warm water, and then wash the drum. Ensure the drum is completely dry before adding food.