"Pre-galv. pipes" refers to pipes that have undergone a galvanization process before they are used in various applications. Galvanization is the process of applying a protective layer of zinc to steel or iron to prevent rust and corrosion. When pipes are pre-galvanized, they are coated with zinc before they are formed into pipes, ensuring that the entire surface, both inside and outside, is protected. This provides excellent corrosion resistance and durability to the pipes, making them suitable for various uses.