The Supa Fat Ball Feeder is designed to take 4 x 100gm Fat Balls. Also comes complete with plastic cap to prevent access / entrapment of small birds. It is always worthwhile cleaning your feeder occasionally with warm water & a mild detergent or a disinfectant solution to avoid a build-up of bacteria. Ensure in your garden that the wild birds have access to a source of water at all times. The Supa Wild Bird Water Drinker is ideal for this purpose.