Gizmo dorks conductive black ABS. The filament ink was tested on 12 volts to 110 volts and at 5000 volts. This ink is soft and seems to have a lower melting point than the typical ABS due to a thermo-conductively enhanced state. This material needs to be purged for over 20 cm3 before trying another color unless utilizing a "fade in" affect on the next lighter print(s). Buying this awesome Conductive 3D Printer Ink from Gizmo Dorks was a good choice for starters. If you were someone who also missed the memo on product specifics: We tested this product without a heated bed. This conductive filament stuck to the taped bed easily at 175C Do try some for less than $99 to show that there is a demand for printing circuits. Happily supplying you with interesting and helpful public domain. Thanks to all of our supporters, thanks to Thingiverse, and thank you for checking into the future of conductive 3-D printing.Rhino 5