TPU Filament MD FLEX 2.85mm 500 gram Dark Blue 3D Printer FilamentTPU Filament MD FLEX 2. 85mm 500 gram Dark Blue 3D Printer Filament Copper 3D MDFlex is an innovative Nanocomposite 3D printer filament developed with a high quality TPU 98A compound and a patented, scientifically validated and highly effective Nano Copper additive. This unique combination of technologies brings the following characteristics to MDFlex. Key features FDA registered filament Compliant to European Union norms: No. 1935 2004 and No. 2023