Our CarbonFil filament is based upon the unique PETG blend of our HDglass compound and is reinforced with 20% ultra-light and relatively long stringer carbon fibres, which has resulted in an exceptionally stiff carbon-fibre reinforced 3D printer filament. CarbonFil is twice as stiff as HDglass and yet it is even 10% more impact resistant, which is a remarkable feature for carbon-fibre reinforced filament.