To complete this set, I need a triple socket to match the single and double sockets found here: http://www.thingiverse.com/thing:7285 http://www.thingiverse.com/thing:7264This thing gives you three ball sockets that can be attached to a rod.By default it is designed to slip/friction fit on a 5/16" rod.This thing, combined with various other ball/socket combinations can make for some very interesting structures.1) Look at your design for places you can use three segments connected to a single rod. 2) Print a few of these 3) Print a few of the ball caps 4) Put ball caps on ends of rods 5) Push rods into sockets 6) Rejoice!There are some constraints as to movement, so you'll have to think about how to properly orient the thing to get the correct angles for your design.