Anti-Magnetic Watches

The problem

Magnets disrupt the hairspring oscillation, making the watch run fast — sometimes by minutes per day. iPad covers, handbag clasps, induction stoves all carry residual magnetism.

The standards

• ISO 764 — basic resistance to 4,800 A/m (60 gauss).
• Soft-iron cage — Rolex Milgauss, IWC Ingenieur. Resists ~1,000 gauss.
• Silicon hairspring — Patek Spiromax, Rolex Syloxi. Non-magnetic at the source.
• METAS Master Chronometer (Omega) — certified to 15,000 gauss.

For 90% of buyers, a modern silicon-hairspring watch is the right anti-magnetic answer — no soft-iron weight penalty.