Siterwell Electronics (赛特威尔电子股份) manufactures self-contained and interlinked smoke alarms, carbon monoxide and gas alarms, heat detectors and connected life-safety sensors from automated plants in Ningbo and Vietnam. Its smoke alarms are LPCB-approved to EN 14604 under certificate 1044a, and the company states parallel VdS, UL 217, UL 268, NF and SAI Global listings for individual lines. With five R&D centres and an annual capacity above fifty million units, it is among the highest-volume Chinese residential detection manufacturers.