Sewon retriever's main components are manufactured from stainless steel, and receive a chroming treatment for resistance to mechanical / corrosion damage and to ensure many years of reliable service. The Sewon retriever has 7 types of heights according to stroke length Any size of retriever is available upon request. The retriever works on a pressure-balanced principle. This safety feature ensures that in the event of sudden pressure release from the system, the retriever will not telescope. The Sewon retriever is designed to operate strictly under mechanical principles, and the number of turns to completely seat or retract a component is a known constant. This allows the operator to have complete control over installation or removal.