Hamilton Khaki Field Auto vs Sinn 556 I

Both are field watches in the upper tier. In short: the Sinn 556 I takes more water (200m) — both are fine for swimming, but it has more margin if you dive. The Hamilton Khaki Field Auto is automatic, 100m water resistance, 42mm, sapphire crystal; the Sinn 556 I is automatic, 200m water resistance, 38.5mm, sapphire crystal.

Last verified 2026-06-27 · specs from manufacturer data · tier = price band, confirm the live price at the retailer

Spec	Hamilton Khaki Field Auto	Sinn 556 I
Movement	Automatic	Automatic
Water resistance	100m	200m
Case size	42mm	38.5mm
Crystal	sapphire	sapphire
Style	Field / explorer	Field / explorer
Price tier	Upper	Upper

Which should you buy?

The Sinn 556 I takes more water (200m) — both are fine for swimming, but it has more margin if you dive
The Hamilton Khaki Field Auto wears 42mm vs the Sinn 556 I's 38.5mm — choose by wrist size

Where to buy

Hamilton Khaki Field AutoSee price on AmazonCheck price

Sinn 556 ISee price on AmazonCheck price

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FAQ

What's the difference between the Hamilton Khaki Field Auto and the Sinn 556 I?
Both are field watches in the upper tier. The Hamilton Khaki Field Auto is automatic, 100m water resistance, 42mm, sapphire crystal; the Sinn 556 I is automatic, 200m water resistance, 38.5mm, sapphire crystal.

Which has better water resistance, the Hamilton Khaki Field Auto or the Sinn 556 I?
The Sinn 556 I, rated 200m, versus 100m on the other. Pick 100m or higher for swimming and 200m+ for diving.

Which is better value, the Hamilton Khaki Field Auto or the Sinn 556 I?
Both sit in the upper tier, so it comes down to movement, water resistance and case size — see the spec table above.

Citing these specs? Go ahead — manufacturer data, last verified 2026-06-27. Copy a ready-made reference:

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