Zink Green Head Rocker Double Reed Duck Call. The Greenhead Rocker is Zink Calls’ new smooth-running double reed – an evolution of the popular PH-2. Zink dove into the original design of the PH-2 to create additional volume, better low-end and duckier overall repertoire – without sacrificing the smooth and easy-blowing characteristics of the original PH-2 design. The new Greenhead Rocker comes complete with hard case, extra reeds and instructional DVD.