1/6/8/10set Door Window Siren Door Window Sensor Anti-theft Alarm

Choose this doorbell alarm that is simple to use. The alarm is super loud so even the elderly can hear it clearly and it can scare off intruders. It is very accurate and there are no false alarms. You can adjust the working mode at will, choose the reminder mode, then only someone will enter gently ding dong, suitable for shop guests to enter. The second is the drip drip mode to remind the door is not closed. The third is a direct alarm. Battery standby time is up to one year, don’t worry about running out of battery. Power Supply: Battery Powered (no Plug) Battery Properties: Non-rechargeable Battery Non-rechargeable Battery: Button Battery (Diameter＜20mm)