fire door hold open device factory

4G fire door alarm direct from Wanlin Fire Protection — 12-year factory experience, WL-FD108 fully certified EN 1155/NFPA 80/CE/FCC/RoHS/REACH. Key specs: 4G LTE Cat.4 + WiFi 6 + Modbus RS485 + Matter, Premium Multi-Door Controller + LCD Display + Voice, AC 230V + 72h backup battery. MOQ 100 units, 25-30 working days, OEM/ODM custom branding available. Serv···