TRG Engineering has the experience and knowledge to provide the best and most economical solution tor your sphere applications. In many situations, TRG Engineering Spheres are more economical and versatile than con­ventional pigs. They will pass through out-of-round pipe, pipe of varying wall thickness, short radius bends, full open through conduit valves, properly designed tees and other obstacles difficult, if not impossible tor con­ventional pigs to pass.