The Rolex Oyster Perpetual Milgauss is designed to withstand magnetic fields of up to 1000 gauss - hence the name MILgauss, MILLE being the French word for 1000. The watch features a metal shield inside the case which surrounds & protect the movement. The shield is made of ferromagnetic alloys selected by Rolex to protect the movement from magnetic fields. Green Sapphire Crystal: the dial is protected by a unique highly scratch-resistant & fade-proof light green colored sapphire crystal. Its light green shade, tinted throughout the entire crystal, turns nearly luminescent at the beveled edges. Polished finished stainless steel case. Polished stainless steel 'Twinlock' crown featuring two sealed zones when the crown is screwed down: the first inside the tube of the crown, the second inside the winding crown itself. Polished stainless steel smooth bezel. Bracelet & buckle features: Brushed stainless steel outer links with polished finished edges. Polished stainless steel center links. Oysterclasp designed deployant clasp. Fitted with the patented Easylink 5mm extension link. Dial: Blue dial. Applied polished steel rimmed hour markers with white luminous fill. Long lasting blue colored illuminating luminous material. Fine orange printed minutes/seconds track & Arabic Numeral 5 minutes/seconds increments. Polished stainless steel hour & minutes with luminous fill. Orange 'lightening bolt' shaped seconds hand. Rolex Caliber 3131, beats at 28,800 vph, contains 31 Jewels & has an approximate power reserve of 48 hours AKA: m116400gv-0002