The Insight Clean Seed Tall Silo Feeder remains on the outside of the cage while the extending food cup goes between the bars and into the cage. The Base screws onto the cage to gauranty a secure fit on horizontal or vertical barred cages. This Feeder has a guard that keeps hulls and debris inside the cage. The perfect feeder for everyday use with no mess and easy refill. Dishwasher safe and available in green, yellow and blue.