This user guide provides instructions for using the Polycom KIRK 4080 explosion-proof handset. [1] It discusses the handset's construction, battery charging, key functions, making and receiving calls, and menu structure. [2] The menu structure allows the user to configure settings like profile, setup, external services, battery status, phone book, and more. [3] The guide provides detailed explanations to help users operate the handset safely and effectively in hazardous environments.