This 6 x 6 in. adapter plate has a 1.5 in. NPT threaded pipe coupler. The coupler includes a cable access hole for safely routing signal cable through pipe interior. It can be used with any standard 1.5 in. NPT pipe or with one of our 1.5 inch adjustable-height suspension adapters (APP-1321 or APP-2446) for drop distances of more than 3.8 ft.