Fit this over your Twin Air Filter when you’re riding in severe conditions such as heavy dust and sand. This coarse foam pre-filter, oiled for maximum benefit, will act as an additional layer of protection and extend the service time between filter cleanings. SHERCO DUST COVER SE-R 125 25- SE-R 250 25- SE-R 300 25- SE-F250 25- SE-F300 25- SE-F450 25- SE-F500 25-