The dimensions of the automatic fish feeder are 16x8 cm. Please see the second product picture for size details of the fish tank automatic hand feeder. Please refer to the actual product of the fish feeder for specific dimensions.The fish tank automatic manual feeder does not contain batteries and requires 2 AA batteries. Please purchase them yourself.The fish tank automatic manual feeder has manual and automatic dual modes, is simple to operate and can be started with one button. The automatic mode of the fish feeder allows you to select time settings and feeding settings, allowing you to experience the fun of feeding fish. The timer feeder is very convenient and easy to use, allowing your fish to eat happilyEasy to Repair: There are two ways to repair an automatic fish feeder. Place the fish tank automatic hand feeder on a freestanding or rim-mounted aquarium. The fish food dispenser features an adjustable clamp base that can be easily attached to the fish tank or can be fixed to a flat surface of the fish tank using the double-sided stickers included with the food timer dispenserThe automatic manual feeder for fish tanks is widely used: the automatic fish feeder is suitable for all flakes, granules, various shapes, and floating fish food. Fish tank feeder for fish, turtles, goldfish, cichlids, guppies, catfish, aquatic pets and more. Digital automatic or manual aquarium timer fish feeders help control food dispersion, reduce food waste, and keep water clean