Antimagnetic Watches

From computers to cell phones to headphones, the ubiquitous presence of magnets in our high-tech lives has the potential to wreak havoc on mechanical watch movements. For example, at Omega’s Tokyo service facility about 80 percent of the watches brought in for after-sales service reportedly have issues with magnetism.

In 2013, Omega tackled these damaging forces with the Co-Axial Caliber 8508 movement, made with nonferrous materials that resist magnetic fields exceeding 15,000 gauss (1.5 tesla). The brand’s groundbreaking antimagnetic technology also powers this year’s Seamaster 300 ($6,600), which is equipped with the self-winding Master Co-AxialCaliber 8400 with its time-zone function and three-level escapement wheel. Available in stainless steel or a mixed metal version with Omega’s Sedna gold alloy, the classic sport watch, first introduced in 1957, is distinguished by a polished, black-ceramic, unidirectional rotating bezel marked with a diving scale in the brand’s Liquidmetal or Ceragold. Omega plans to equip all its watches with antimagnetic movements, which can be showcased through a sapphire crystal case back since there is no soft-iron inner case, the traditional construction for antimagnetic timepieces.

Ball Watch’s Engineer II Magneto S ($3,399) puts a novel twist on the protective inner case with its patented A-Proof device made with mu-metal—an alloy of nickel, iron, copper and molybdenum—which has been used for magnetic shields in other industries, but never before in watchmaking. Mu-metal can shield the movement from magnetic fields up to 80,000A/m, which is comparable to 1,000 gauss. (To achieve antimagnetic status, a watch must withstand a 4,800-A/m magnetic field while neither gaining nor losing more than 30 seconds per day.) Aside from the exotic material used, the A-Proof device is engineered with a diaphragm mechanism that opens and shuts with a turn of the bezel, allowing you to safely enclose the movement when desired or retract the shield to admire the movement through the sapphire crystal case back.

Launched in 1956, Rolex’s Oyster Perpetual Milgauss was an early pioneer in antimagnetic technology, resisting magnetic fields up to 1,000 gauss, as the name suggests. Since the 2000s, Rolex has incorporated an oscillator and an escapement made of resistant paramagnetic materials in addition to surrounding the movement in a shield made of ferromagnetic alloys within the Oyster case, a design patented in 1954. This year, the Milgauss ($8,200) has a new look with an electric blue dial under its distinctive green sapphire crystal, which debuted in 2007. The vibrant dial color was chosen to play off the signature lightning-bolt-shaped seconds hand. Rolex may have developed the Milgauss for 50s-era engineers and technicians who encountered magnetic fields as they worked, but antimagnetic watches aren’t just for scientists anymore.