Rotate the wave design Versa Perch to vary the proximity to the port. Flip it over for more options. Debris discarded by birds drops through the airy structure. Great for finches and other flocking birds. No tools - threaded wing nut attaches perch to feeder. Wing nut hook - hang suet, or another feeder underneath, holds 30 lbs. Fits: Ring Pull Feeders, Classic Feeders and New Generation Feeders.