Review on Mercedes Benz SummerFit Windscreen Concentrate by Trevor Blazis

Works well when used as intended. As for tap water, I'm not sure if it's filtered or distilled. The Revain photo gives the illusion that the concentrate tank is huge, but it's actually quite small. Only 40ml as described. You only get 1 gallon of washer fluid because it is diluted with 1 part solution concentrate to 100 parts tap water. 1 gallon of water is about 4000 ml. You could probably use a 1/2 price product with no adverse effects on the system. But it comes in handy when you're on the go. Be sure to fill the 1 gallon jug FIRST before pouring the solution or too many bubbles will form.