# Orient Kamasu vs. Hamilton Khaki Navy Scuba: How Much Watch Does an Extra $600 Buy?

> The Hamilton brings a Swiss movement with 80 hours of reserve and a smaller case. The Orient brings twice the depth rating and a longer warranty, and costs $600 less.

URL: https://wristmetric.com/comparisons/orient-kamasu-vs-hamilton-khaki-navy-scuba
Section: Comparisons
Published: October 1, 2026 (updated October 6, 2026)
By: Wristmetric Staff
Brands: Orient, Hamilton

**The short answer.** The extra money buys a better movement and a more refined watch, but not a better [dive watch](https://wristmetric.com/dive-watches/). The [Hamilton](https://wristmetric.com/brands/hamilton) Khaki Navy Scuba has an 80-hour Swiss H-10 with a Nivachron hairspring, an anti-reflective sapphire crystal and a smaller 40mm case. The [Orient](https://wristmetric.com/brands/orient) Kamasu has twice the depth rating, a longer warranty and a published accuracy spec, and at $375 it costs $600 less.

| | Orient Kamasu | Hamilton Khaki Navy Scuba Auto 40 |
|---|---|---|
| Price (US) | $375 (edge) | $975 |
| Reference | RA-AA0003R39B | H82425110 |
| Movement | Orient F6922, automatic | Hamilton H-10, automatic (edge) |
| Power reserve | About 40 hours | 80 hours (edge) |
| Rated accuracy | +25/−15 sec/day (edge) | Not published |
| Hacking | Yes | Not published |
| Hand-winding | Yes | Not published |
| Jewels | 22 | 25 |
| Beat rate | 21,600 vph | 21,600 vph |
| Case diameter | 41.8mm | 40mm (edge) |
| Thickness | 12.8mm | 13mm |
| Lug to lug | 47mm | Not published |
| Lug width | 22mm | 20mm |
| Crystal | Sapphire | Sapphire, anti-reflective (edge) |
| Caseback | Not published | Solid, screw-down |
| Water resistance | 200m (edge) | 100m |
| Bezel | Unidirectional, 120 clicks, stainless steel bezel | Unidirectional 60-minute, aluminum |
| Crown | Screw-down | Screw-down, with guards |
| Lume | Luminova | Super-LumiNova |
| Bracelet / strap | Steel bracelet, fold-over clasp with safety | Three-row steel bracelet, folding clasp |
| Warranty | 3 years (Orient Watch USA) (edge) | 2 years (international) |

## Price

The Kamasu, reference RA-AA0003R39B, is $375 at [Orient Watch USA](https://www.orientwatchusa.com/products/ra-aa0003r39b). Hamilton sells the Khaki Navy Scuba Auto 40mm, reference H82425110, for $975. The Hamilton costs $600 more, or 2.6 times as much.

That is the number this comparison works with. The question is not whether the Hamilton is a better watch than the Kamasu in some respects. It is. The question is whether those respects are worth $600.

## Design

The Khaki Navy line is part of how Hamilton keeps its military and tool-watch history alive, and the Scuba is its dive watch. The 2026 refresh gives the 40mm model a silver-white dial with a stamped wave texture, and Hamilton has also updated the typography on the unidirectional 60-minute bezel. The crown is guarded.

The Kamasu has been on the market since around 2019, but Orient's dive watch history runs much further back, to the King Diver 1000 of 1965. The Kamasu's case is brushed on top with polished sides. Its unidirectional steel bezel turns in 120 clicks, and the reference covered here has a deep wine red dial.

Both are conventional dive designs. The Hamilton's pale textured dial is the more unusual choice in the category, and the Orient's red dial is the bolder one. Neither is more correct, and taste will settle this round.

## Movement

This is the Hamilton's strongest ground. The H-10 is built on the Powermatic 80 base that the Swatch Group also uses at [Tissot](https://wristmetric.com/brands/tissot). It has 25 jewels, beats at 21,600 vph and runs for 80 hours. It also uses a Nivachron balance spring, a titanium-based alloy that the Swatch Group says reduces the effect of magnetic fields and resists temperature changes and shocks.

The Kamasu's F6922 is made in Akita Prefecture by Akita Epson. It has 22 jewels, the same 21,600 vph and about 40 hours of reserve, with hacking, hand-winding and a day-date display. The Hamilton shows only the date.

The reserve gap is the practical difference. Eighty hours is a little over three days, enough for a watch taken off on Friday evening to still be running on Monday morning. Forty hours is not. The Nivachron spring adds a second advantage, and Orient publishes no comparable claim for the F6922.

Hamilton's hand-wound H-50 shares the 80-hour reserve and the Nivachron spring, and we cover it in our [Khaki Field Mechanical 38 review](https://wristmetric.com/reviews/hamilton-khaki-field-mechanical-38-review). Orient's side of the story is in [our explainer on its in-house movements](https://wristmetric.com/culture/inside-orients-in-house-mechanical-movements).

The Hamilton takes Best Movement, and it is not close.

## Case and Dimensions

The Kamasu measures 41.8mm across, 12.8mm thick and 47mm lug to lug, with 22mm lugs and a screw-down crown.

The Hamilton measures 40mm across and about 13mm thick, with 20mm lugs, a screw-down crown with guards and a solid screwed caseback. Hamilton does not publish a lug-to-lug figure, and we have not been able to confirm one.

So the Hamilton is 1.8mm narrower, and the two are effectively the same thickness. Orient does not state the Kamasu's caseback type, but secondary sources describe it as solid, so neither watch shows its movement.

## Dial

The Hamilton's lacquered silver-white dial has a stamped wave texture, with applied indices in the form of wedges at 12, 3, 6 and 9 and dots elsewhere, and Super-LumiNova. The date sits between 4 and 5 o'clock, and reviewers note that it is harder to read against this dial.

The Kamasu's dial is wine red. Reviewers describe its finish as sunburst, while Orient simply calls it red. Applied indices with silver surrounds use dots at most hours, rectangles at 6 and 9 and a trapezoid at 12. The hands are an arrowhead and a lance, the lume is Luminova, and the day and date sit at 3.

The Hamilton's textured dial is the more interesting surface, but its date window is a known weak point. The Orient's day-date is easier to read and gives more information. This round is close to even.

## Crystal

Both watches use sapphire. The Hamilton's has an anti-reflective coating, which Hamilton specifies on its product page. Orient does not mention a coating for the Kamasu.

An anti-reflective coating reduces glare across the dial, which matters on a dive watch that is meant to be read at a glance. It is a modest advantage, but it is a clear one, and the Hamilton takes this row.

## Accuracy

Orient rates the F6922 at +25/−15 seconds a day. Hamilton does not publish an accuracy rating for the H-10.

That does not mean the Hamilton is less accurate. It means there is nothing to compare, and a buyer has no published tolerance to hold the maker to. On transparency, the Orient wins this row. On actual timekeeping, the specification sheet cannot settle it. Our guide to [reading a watch spec sheet](https://wristmetric.com/culture/how-to-read-a-watch-spec-sheet) explains why a missing figure is worth noticing.

## Water Resistance

The Kamasu is rated to 200m and the Hamilton to 100m. Both have screw-down crowns, and neither is certified to ISO 6425, the international standard for divers' watches. Orient makes no ISO claim for the Kamasu, and the Hamilton's rating is not an ISO rating either.

The Kamasu wins this row clearly, with twice the rated depth for less than half the price.

> The Hamilton is the better-made watch. The Orient is the better-specified diver.

For most owners, 100m with a screw-down crown covers swimming and snorkeling. But this is a comparison of two dive watches, and on the one specification that most directly defines the category, the cheaper watch is ahead.

## On the Wrist

On the published dimensions, the Hamilton is the more compact watch. Its 40mm diameter is 1.8mm smaller than the Kamasu's, and a 40mm diver suits a wider range of wrists than a 41.8mm one. The missing lug-to-lug figure makes a full comparison impossible, but the diameter points one way.

The two cases are about the same height, so neither has an advantage under a cuff. The Kamasu's 47mm lug-to-lug is compact for its diameter, which narrows the gap.

The lug widths differ too. The Hamilton's 20mm lugs suit its smaller case. The Kamasu's 22mm lugs give it a broader, sportier stance. On the numbers, the Hamilton is the easier fit.

## Quality

The Hamilton's specification reads like a more expensive watch, and it is one. An anti-reflective sapphire crystal, crown guards, a screwed caseback, a lacquered stamped dial, Super-LumiNova and a Nivachron balance spring add up to a more thoroughly built package. It comes on a three-row steel bracelet with a folding clasp.

The Kamasu's oyster-style bracelet is 316L steel with split pins and a stamped fold-over clasp with a safety catch. Reviewers report hollow end links, which Orient does not confirm. That is where the Kamasu's price shows most.

The Hamilton takes Best Build. Neither maker publishes enough about case finishing to go further than that.

## Long-Term Ownership

Orient Watch USA offers a 3-year warranty on the Kamasu. Hamilton offers a 2-year international warranty. On a watch that costs $600 more, the shorter cover is a weak point.

Against that, the Hamilton's 80-hour reserve and Nivachron spring are advantages that last for as long as the watch is worn. A watch that survives a weekend off the wrist needs resetting less often, and a hairspring made to resist magnetism reduces the risk of one common cause of a mechanical watch suddenly running fast.

Both have sapphire crystals and screw-down crowns, so both should hold up well to daily wear.

## Value

At $375, the Kamasu offers a sapphire crystal, 200m of water resistance, a screw-down crown, a 120-click bezel, a day-date and a published accuracy rating, with a 3-year warranty. It is hard to find a more complete dive watch specification at that price.

The Hamilton's extra $600 buys four real things. It gets twice the power reserve, a magnetism-resistant hairspring, an anti-reflective coating and a smaller case. In return, it gives up half the depth rating, a year of warranty, the day display and a published accuracy spec.

That is a fair trade for some buyers, but it faces strong competition at $975. The [Christopher Ward](https://wristmetric.com/brands/christopher-ward) C60 Trident Pro 300 was selling for $878 at the time of writing, with 300m of water resistance, a ceramic bezel and an anti-reflective sapphire crystal, though its reserve is 38 hours. We cover both in [The Watches We'd Actually Buy Under $1,000](https://wristmetric.com/buying-guides/the-watches-we-would-actually-buy-under-1000).

For a closer rival to the Kamasu at its own price, see [Orient Kamasu vs. Seiko 5 Sports](https://wristmetric.com/comparisons/orient-kamasu-vs-seiko-5-sports), and for the full picture of the Orient, our [Kamasu review](https://wristmetric.com/reviews/orient-kamasu-review).

## Verdict

- Best Value: Orient Kamasu
- Best Movement: Hamilton Khaki Navy Scuba Auto 40
- Best Build: Hamilton Khaki Navy Scuba Auto 40
- Editor's Pick: Orient Kamasu

The extra money buys a better watch, but not a better dive watch. The Hamilton earns Best Movement and Best Build on its 80-hour H-10, its Nivachron hairspring, its anti-reflective sapphire and its crown guards, and its 40mm case will suit more wrists. Anyone who rotates between watches and wants one that is still running on Monday will feel the difference in reserve every week.

But the Kamasu is rated to twice the depth, carries a longer warranty and costs $600 less. For a buyer who wants a dive watch first, it is the one we would choose, and the money saved is enough to buy a second watch.

Prices are US dollars as charged by the maker at publication. Verify specifications with the manufacturer before buying. Editorial policy: https://wristmetric.com/editorial-policy/