What makes a self-locking insert self-locking? and, how can I know what the locking feature is?
Hi most probably knocked the exhaust system
Any fire alarm system can use a siren for a signalling device. They also can use bells,horns, strobes or any combination of the above. Installing a fire alarm system in a new building is something that is fairly complex and should be installed by a qualified person. Depending on your location most places require a qualified person to do this job.
