These connectors are for standard 1/2" PVC Schedule 40 Pipe (.625 OD). The motivation for me was to have a "greenhouse" structure. So I designed them to distribute water.To make a dome, you'll need 26 connectors (20 hexagons and 6 pentagons) and 65 struts (35 of length A and 30 of length B). To determine your strut lengths, use a calculator: http://www.desertdomes.com/dome2calc.html http://www.simplydifferently.org/Geodesic_Dome_Notes?page=3#2V/L2 Refer to this diagram for assembly: http://www.desertdomes.com/graphics/dome/2vdiagram.gif