This item is a printable rack allowing you to hang your test leads it. The rack can be expanded by printing multiple copies and then either bolting or gluing together. Thanks to Jim McCall for the SolidWorks model. Print out the STL file on a 3D printer, clean it up and then mount it on a vertical surface. You can combine as many copies as you need to expand the rack.As an alternative to screwing the modules together, a 3mm piece of plastic filament can be glued into the screw holes and then cut flush. This will make for a cleaner join between the blocks.