Cross-section through the frame of the Affenzahn pushbike made with glass fibre reinforced polyamide (PA0-GF), nylon. The lightweight hollow frame is made using water injection technology (WIT). Similar to gas injection, during the moulding cycle, water is injected, forming a bubble inside the molten plastic, pushing it into the mould cavity and forming a hollow core. It is made with coloured PA, so not pigment is required in the paint layer, and reduces the visible damage from surface scratches. The cut plastic has been painted black for this sample to show off the technology.