This Schneider Electric Harmony K operating headis designed to fit in a 29mm diameter hole. This operating head is designed to meet most industrial and process control application thanks to a compact size, an easy integration with 16 millimeter and 22 millimeter diameter units and has several selection functions. Simple and modular design to allow for easy installation. Designed to fit in 16-22mm cutout, ensuring compatibility when installing in pre-existing machinery. Sturdy plastic body resistant (strength) to shocks and corrosion. IP65 on its front part allow for installation in harsh (heavy) environment or outdoor.