You can fill the Rush LED Tumbler with dry food or treats. The cat must play with this wobbler to get the food out. The built-in LED light changes color constantly, very nice as extra attraction to the toy. The Led light goes off automatically when the toy is not touched. The battery is not replaceable, but the function of this snack wobbler is of course preserved! You can also use this Mouse Tumbler if your pet tends to eat too fast. Fill the wobbler with kibbles and it will gradually release the food during play.