This is a simple spot that takes up to 7 (5mm) LEDs. The spot has four connectors that allow assembling larger light installations. We are using these spots as part of our mikrokopter project since three of them arew below 40g1) Print :-)2) Parts and holes are tight-fit. Depending on your print-settings some sanding might be needed.2) Use a LED calculator (http://www.spaceflakes.de/led-rechner/) to find the needed layout and resitors. In our case (12V) we are using three parallel lines (3,2,2 with 100, 220, 220 Ohm resistors). 3) To connect spots there are two different ways:Cut 3mm threads in each of the connector holes an use a threaded M3 rod to connect. These rods can be printed as well (http://www.thingiverse.com/thing:31363)4) To change the size or number of LEDs, simply design/print a different plate.