Scraper disc pigs are bidirectional models designed for heavy-duty cleaning, although they can also be used for batching or gauging. They generally seal less effectively than pigs with dedicated sealing discs. However, models with multiple scraper discs, such as the BGD-4, can provide sealing comparable to a multi-disc pig. Their thicker scraping discs deform less than sealing discs, producing a bulldozing action rather than a smooth sliding seal. High differential pressure and flow volume are usually required, especially when moving heavy debris. Brushes are optional.