PETG LW filament is a functional material for heat-resistant, lightweight aeromodels that can be foamed in-line at high temperatures during the printing process to achieve lower part densities (down to 0.7 g/cm3) and weights. Thanks to the high elongation at break and impact resistance of the PETG base material, the foamed part has high toughness and excellent interlayer bonding, and PETG LW printed models are weather and heat resistant, making them suitable for outdoor modeling. The high-temperature printed parts have a frosted matte surface texture without the yellowing phenomenon commonly seen with foamed filaments, and are easy to paint and accurate in color. Thanks to the in-line controlled closed cell foaming technology, the printed parts are waterproof. PETG LW filament is the ideal choice for all kinds of lightweight, heat-resistant, high-toughness and waterproof modeling needs.