BMW 1 SERIES F40 19+ GLOSS SINGLE EXIT REAR DIFFUSER. Made From Premium ABS Plastic. Single Exit Diffuser Gloss Black 0. This rear diffuser is designed for the BMW 1 Series F40 19+, featuring a glossy black finish and suitable for M Sport models with a single exhaust. Made of ABS material in the United Kingdom, it is a performance part that enhances the vehicle’s styling.