Hongkong and Shanghai Total Co., Ltd. is producing smoke alarm, smoke detector, personal alarm, door and window alarm, Carbon Monoxide Alarm, gas alarm, natrual gas alarm, co alarm, co gas alarm, Carbon Monoxide detetor, coal gas alarm, co detector, combustible gas alarm, heat alarm, heat detector, alarm detector, wireless doorbell, remote control doorbell, remote control socket, light control switch, PIR sensor alarm, PIR motion sensor, home security system, security fittings, video doorphone, wireless video doorphone, video door entry system, doorphone.