it agreed to acquire the Wells Fargo Alarm business of Borg-Warner Security Corp. for $425 million.

Wells Fargo Alarm, based in King of Prussia, Pa., makes electronic security products for commercial and residential clients and has annual revenue of $250 million.

Tyco makes disposable medical products, fire-protection and electronic-security systems, packaging materials and industrial items. It is based in Bermuda, but has its US headquarters in Exeter, New Hampshire.

The company, which has been rapidly buying large and small firms, has annual revenue of $13 billion. Wells Fargo Alarm will be integrated with its ADT Security Services business.

Borg-Warner, based in Chicago, provides security services such as armed guards and couriers, alarms, closed circuit TV and access-control systems under the Wells Fargo, Burns and Globe brand names. It has annual revenue of $1.5 billion.