The SF340 has been specially designed for permanent, secure installation and is ideal for use by local authorities, housing associations and any organisation responsible for the safety of tenants and the maintenance of their homes. The SF340 series of alarms incorporate a unique module replacement system. There are no re-wiring or main unit replacement costs, just a simple, clip-in module to change once every 5 years. This results in low ownership costs and minimal maintenance. Locking screws also ensure that only authorised persons can gain access to the unit.