The Heavy Duty Cathedral Ceiling Adaptor can be used with 1.5"-11.5 NPT extensioncolumns (EXT, AEC models only) to securely mount and support a projector or flat paneldisplay from an angled ceiling. This adaptor offers 95°/-5° of adjustment and includesa security slot for theft resistance. The ACC-CCPHD is a low-profile, secure solution tosupport nearly any projector or display in an angled ceiling application.