Perhaps one of the most impressive additions to the Rolex series of professional watches is the Oyster Perpetual Milgauss. Introduced in 1956, the Rolex Milgauss utility watch was marketed for use while working in highly magnetic environments. An innovative "shielding" system utilizes ferromagnetic alloys to protect the calibre 3131 perpetual movement from up to 1,000 gauss. Ideal for scientists and engineers, the Milgauss will provide a highly reliable reading wherever your work takes you. The Milgauss reference 116400GV is a recent addition to the Rolex line and features 904L stainless steel, a distinct green scratch-resistant sapphire crystal, a Twinlock waterproof screw-down crown, and a flat link Oyster bracelet and folding Oysterclasp. A handsome Z-blue dial is set with highly visible Chromalight markers and a distinct orange lightning bolt seconds hand.