50mm Wireless SOS Button 433MHz EV1537 | 3.3V–6V RF Emergency Panic Button

50mm round wireless SOS emergency button with 433MHz RF transmission and EV1537 encoder chip. Operates on 3.3V–6V DC battery power and offers up to 40 meters wireless range in open area. Provides approximately 2-second RF pulse output, suitable for alarm panels, panic alarm systems, security systems, and microcontroller-based RF receiver projects.