Description. 100% brand new and high quality. Smoke sensing alarms achieve fire prevention by monitoring the concentration of smoke. When the concentration of smoke exceeds the limit, smoke sensing occurs with an audible and visual alarm and outputs an alarm signal. Smoke sensors are widely used in urban security, neighborhoods, factories, companies, schools, homes, villas, warehouses, resources, petroleum, chemicals, gas distribution and many other areas. It is sensitive to smoke, so it has stopped many fires from happening! Technical parameters. >Operating voltage: 9V carbon or alkaline batteries (not included) >Static current: 10uA >Alarm current: 35mA >Smoke sensitivity: Class II >Alarm sound: >80dB >Transmission frequency: 433MHz >Transmission distance: 100m (open distance) >Working temperature: -10~50 >Working humidity: 10%-90%RH Product includes. 1*smoke alarm (batteries not included) (No box, no accessories other than the product included!) Notes. 1. The monitor used is not the same, the computer is not the same, the angle of the photo is not the same, there may be angle colour problems. 2. Pure manual measurement, there may be 0-1cm error.