The Rain-X Windscreen Repair Kit is easy to use and takes only 30 minutes to repair a variety of small damage to a windscreen. It minimizes the appearance of chips and cracks, and stops them from spreading across your screen. With its advanced resin formula this is great for multiple repairs on all types of laminated windscreens. It works best on round damage not more than one inch/2.5 cm in diameter, and cracks not longer than 12 inches/30 cm.