This is based on the LED used by ScribbleJ : http://www.thingiverse.com/thing:6244 . This one use the same 80mm version from Dealextreme. I wanted something that can be bolted without fear that it will move or fall. It's easy to bolt it to the Cupcake Z bed and you have place for the wires. The LED Ring snap in place and stay in place. No Glue needed. I printed it in ABS to help since PLA is less "flexible".