On Germany's Autobahn when you are travelling at 150mph and a bug meets your windshild, you need a product that will deal with it...one that will cut through the oily road grime. P21S Windshield Wash Booster was developed for these conditions.....it makes streaking a thing of the past. Add a pre-measured amount to your fluid resevoir and let your wipers work to their fullest. One bottle does up to 26 quarts of washer fluid.