Viking Standard/Quick Response Extended Coverage Light Hazard ELO Concealed Pendent Sprinkler VK618 is a thermosensitive spray sprinkler pre-assembled with a threaded adapter for installation with a domed cover. The sprinkler is designed with an extra-large orifice and a special deflector to meet Light Hazard density requirements for specifically listed extended areas of coverage at lower pressures than standard orifice or large orifice sprinklers.