BIG jobs require BIG quantities. Roadblock is a silica spray sealant that incorporates the durability and hardness of glass in an easy to apply spray and wipe formula. Roadblock will leave your car, boat, or recreational vehicle with a glassy, smooth, and protected finish for up to 6 months. Roadblock can be used on all surfaces like paint, chrome, glass, and even plastic. This product is great for refills on your 16 or 32 oz. bottles and most importantly will save you money.