Silverhook All Seasons Screen Wash has a no smear formula that keeps windscreens spotless and free from road grime and bugs. The concentrated formula can be diluted with water for all year use. When used undiluted it is effective to 8¸C. Dilution rates: Summer - 1 Part Screen Wash : 6 Parts Water. Winter - 1 Part Screen Wash : 2 Parts Water. Severe Conditions - Use Undiluted. Size: 5 litre.