The 4th prototype is very experimental and is used to try new things. On the 1st iteration it was build from aluminium tubes and printed parts made from Extrudr PETG & ColorFabb nGen filament. After a rebuild we've increased the machine height by 200 mm and also changed the aluminium tubes for carbon fiber tubes. The final machine's parts were printed with Extrudr Green-TEC filament. On this machine we're using a dual extruder / single nozzle setup. We've developed a filament splitter (fila_switch)that allows to change the filament during a print, but use only one hotend. The machine is equipped with an 0.8mm E3D Volcano hotend, two Bondtech QR extruders (1.75 mm), a 230V/450W heated bed with a FR4 epoxy surface, a Cohesion 3D ReMix controller, 5x TMC2208 stepper drivers and a Raspberry Pi 3 running OctoPrint. This machine has a usable Z height of around 500 mm (depending on the used hotend).