The Poly APP-51 Hanging Electronic Switch is an accessory designed for compatible wireless headsets and desk phones. It allows remote answering and ending of calls directly from the headset, eliminating the need to manually lift the handset. Suitable for professional offices and call centers that use supported Poly/Plantronics headsets and compatible desk phones. With SKU and MPN 38439-11 and EAN 017229137363, the APP-51 is a practical connectivity accessory that enhances convenience, workflow efficiency, and hands-free call control.