The Yale door contact alarm's siren will sound if the door is opened and the magnetic contact broken. The siren's loud at 100dB+. Installation is easy and wire-free. It can be mounted on the wall or left free-standing and is expandable using touch and link technology. The alarm has a 5-digit, programmable security code. Suitable for flats and houses, sheds and caravans, the new stand-alone alarm system offers the ultimate in flexible security.