Rain-X Original Glass Treatment is a solution designed to improve the visibility through your vehicle's windshield. Apply Rain-X to the exterior glass, and it will repel water, sleet, and snow more effectively than a windshield without any treatment. A study has shown that stopping time in poor weather can be improved by up to one second by applying the glass treatment. The glass treatment is available in a 3.5 oz squeeze bottle and a 16 oz spray bottle for about $4 and $10 respectively. You apply treatment to a clean windshield with a cloth, and for best protection you should reapply every couple of weeks. There is also a windshield washer fluid additive available so you can deposit Rain-X on your windshield with every spritz.