Originally created in 1956 for engineers and technicians who are exposed to magnetic fields which disrupt the watch accuracy, the Milgauss was designed to resist magnetic interference up to 1,000 gauss, hence the name “mille” which is French for “thousand.”

The big Milgauss news for 2014 is the new Z blue dial — combined with the green sapphire crystal and orange lightning-bolt shaped seconds hand. The name “Z Blue” comes from the zirconium content in the alloy of the dial.

The Milgauss is presented in a 40 mm 904L stainless steel case with a ferromagnetic alloy shield that surrounds the movement inside the case (an invention that was patented by Rolex is 1954). In addition, the caliber 3131’s oscillator and escapement are made of paramagnetic materials that have been used in Rolex movements since the 2000s.

According to Rolex, “The escapement of the Milgauss features a paramagnetic escape wheel made of a nickel-phosphorus alloy. This component is produced using a micromanufacturing technology (UV-LiGA) that is entirely mastered in-house. The oscillator, the true heart of the watch, has a blue Parachrom hairspring patented and manufactured by Rolex in an exclusive alloy of niobium and zirconium. Insensitive to magnetic fields, the Parachrom hairspring offers great stability when exposed to temperature variations and remains up to 10 times more precise than a traditional hairspring in case of shocks.”

The caseback is solid and screwed in with a special tool. The crown features a patented Twinlock system, good for 100 meters of water resistance.

The steel bracelet features a Rolex-patented Easylink rapid extension system that allows the wearer to easily increase the bracelet length by approximately 5 mm, for additional comfort. (Ref. 116400 GV)