Our 4-Star Mega Hub Dome Connector is used as a base connector for all Sonostar Mega Domes, where the base is at ground level. 'Mega' refers to the size of the hubs and differentiates them from 'standard' hubs, which fit 1/2" PVC. These are the same connectors that come in Sonostar Mega Dome and Mega Sphere kits. Typically, they are used at the base of a dome, but they can also be used in a doorway, where you remove struts for an opening and you want it to be flush, without the 6-way arms sticking out. Designed to fit either 1" or 1.5" Schedule 40 PVC.