WSO-PR-N00 & I00 High quality loop powered device designed to alert building occupants of an emergency. Featuring fast and simple installation and control it is powered by the fire panel via the loop wiring. Control of the device is enabled using on-board switches or via the digital protocol using the control panel. WSO-PR-N00 - Red Wall Mount Sounder, with pure white skirt - non isolated. WSO-PR-I00 - Red Wall Mount Sounder, with pure white skirt - isolated. The range is installed simply by a twist fit onto the B501AP base.