The Stopper Dome Sounder / Speaker / Strobe is a tough cover with advanced features, that is designed to provide maximum protection for the smaller sounder, speaker and strobe signal units of the new generation of fire protection systems. Moulded in tough, clear UV-stabilised polycarbonate material, the covers are suitable for either flush or surface mount installations. STI offers circular back boxes as well as an appliance mounting plate that eliminates the need for an electrical outlet.