An operator adapter is required to install a disconnect in Bulletin A21S4, A28S4 and WS2D HOFFMAN enclosures that have a preferred cutout. Operator adapters include components needed to interlock the master door with the disconnect operating mechanism. Panel drilling and installation instructions are furnished with each operator adapter. Each brand and type of disconnect requires a different operator adapter. Be sure to select the proper operator adapter and enclosure for the disconnect that you have selected.