The 3611 Magnetic railshoe with 5/8 thread is a magnetic track prism adaptor with rotatable 5/8“-male-thread. It’s made of aluminum, high grade steel. Features: • Magnetic mounting • On-board bubble vial • Height to center of prism: 125mm. Contains: • NdFeB Strong Magnet *3 • 20*10mm Cylinder Magnet*2 • 40*10mm Cylinder Magnet*1 • Round Bubble Level *1 • Alloy Aluminum L-shape Base *1 • 5/8inch Threaded Mount *1