RED SPONGE for original filter box Self-extinguishing, expanding polyurethane filter elements with an increased air and filtering capacity, designed for sporting applications. You can recognise Red Sponge immediately by its distinctive Malossi red colour and the yellow trademark. Characteristics: - Increased thickness with calculated porosity. - Optimum filtering characteristics when dry which can be improved by moistening with Malossi oil. - Selected material produced exclusively for specific use. Perfectly interchangeable with the originals they are especially suitable for high-performance engines.