Leupold keeps their successful tradition of delivering state-of-the-art sport optics alive with their persistent attention to detail, precision and quality. This American optics company, located in Portland, Oregon, pioneered the process of nitrogen purging to waterproof riflescopes in 1947. Since then and to this day, Leupold continues to develop new technologies, and use advanced materials to push the envelope to produce some of the world's finest sport optics. Leupold's Mark 4 Mounting Rings are an excellent mounting option for riflescopes with a 30mm main tube. These rings are durable, repeatable, and designed to fit Mil-Std 1913 Picatinny rail systems. These rings are manufactured from steel, with torx head drive screws. Torx head screws feature a deep-engaging lobe design that inhibits stripping by ensuring proper driver alignment. These high mounting rings raise your scope 1.06" over your mounting rail