4-Pack Sonic Wireless/battery Operated Door & Window Alarms Wireless/Battery Operated ~ Ideal for doors/windows/gun & medicine cabinets. NO TOOLS are needed to set-up!! When Magnetic Contact is broken the LOUD 90db alarm sounds. Unlike most other similar items, these Security & Safety Devices also feature a Chime Mode! Batteries are included Four (4) Alarms per Package Alarm & Chime Modes To Choose From Loud 90db Siren/Alarm Set-up A Security "Perimeter Protection Zone" In MINUTES !!