Add mobility to any Whitney Brothers toddler-sized cube, preschooler-sized cube or Nature View Reading Haven! Simplicity is genius with this easy-to-assemble caddy that gives custom-fitted mobility with locking casters to Whitney Brothers Cubes. Includes four discreet pre-drilled screw holes and screws to secure a cube to the caddy. All edges are rounded over and sanded smooth for safety. Constructed in beautiful, durable birch plywood in safe, non-toxic natural UV finish that won't yellow and withstands rigorous use.