The Challenging Paddle Wheel Forager Bird Toy is made of durable polycarbonate to stand up to even the toughest beaks, and is a very advanced foraging device! Just unscrew the wing nut and fill top chamber with food or treats. Wing nut must be completely tightened - spins with bottom paddles. Birds must continue turning the top wheel which rotates the baffles to release small portions of food in the recovery tray below. The unit attaches to the cage with double post screw-on fittings. Recommended for medium and large size birds. Dimensions: 9" length x 4.5" width x 5" height