Topaz’s Weatherproof Box Holder is constructed of corrosive resistant die cast zinc and is the single-product solution to affix electrical boxes. Designed to stub up electrical enclosures above concrete slabs and suspend electrical boxes and fire alarms between bar joists; easy to handle and install. Featuring a 1/2" knockout size; meets the stringent requirements of 2011 NEC Section 314-23, cULus approved.