Mechanical Face Seals have been utilized with outstanding success in transmission, pumps, axles and drive machines. The special cast iron material has provided extra-ordinary wear-resistant solutions for a variety of demanding applications such as construction machinery, agricultural equipment, mining machinery, drive machines for tracked vehicles and many other applications. MDO type is characterized by the use of an O-Ring as the secondary sealing element, consisting of two identical metal rings which seal against each other on a lapped seal face.