WADT Inc.
WBanham Group
WSiemens
WS.H. Couch
WCSL Group Ltd
WFire-Lite Alarms
WG4S
WGents' of Leicester
WHalma plc
WHoltzer-Cabot
WKnight Security Systems
WMessageNet systems
WNAFFCO
WNotifier
WSecom
WSecutron
WStandard Electric Time Company
WSystem Sensor
WUTC Climate, Controls & Security
WVector Security