Hamilton Khaki Aviation vs Longines Spirit
Hamilton Khaki Aviation Pilot Day Date Auto H64615735 vs Longines Spirit L3.810.4.53.6, compared on the specs each brand publishes.
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The short answer
Two pilot-style automatics at different price points, compared on published specs.
- Case size: the Hamilton Khaki Aviation Pilot Day Date Auto H64615735 is 2 mm larger (42 mm vs 40 mm).
- Thickness: the Longines Spirit L3.810.4.53.6 is 0.35 mm thicker (12.2 mm vs 11.85 mm).
- Power reserve: the Hamilton Khaki Aviation Pilot Day Date Auto H64615735 is 8 hours longer (80 h vs 72 h).
- Price: the Hamilton Khaki Aviation Pilot Day Date Auto H64615735 lists for $1,475 less in the US ($1,075 vs $2,550).
- Calibre: Hamilton Khaki Aviation Pilot Day Date Auto H64615735 has H-40; Longines Spirit L3.810.4.53.6 has L888.4.
Side-by-side specs
| Spec | Hamilton Khaki Aviation Pilot Day Date Auto H64615735 | Longines Spirit L3.810.4.53.6 |
|---|---|---|
| Case diameter | 42 mm | 40 mm |
| Thickness | 11.85 mm | 12.2 mm |
| Lug-to-lug | Not published by Hamilton | 49.7 mm |
| Lug width | 20 mm | 21 mm |
| Calibre | H-40 | L888.4 |
| Movement | Automatic | Automatic |
| Power reserve | 80 h | 72 h |
| Water resistance | 100 m | 100 m |
| Crystal | Sapphire | Sapphire |
| Case material | Stainless steel | Stainless steel |
| Ships on | Leather strap | Bracelet |
| Weight | Not published by Hamilton | 142.4 g |
| US list price | $1,075 (US list) | $2,550 (US list) |
| Dial | Black | Black matt |
| Status | In production | In production |
| Suits wrists of about our sizing guide | 16.8–18.7 cm | 16.8–17.9 cm |
Specs summarised in our own words from the brand's product pages: H64615735 source (checked 3 Nov 2026) L3.810.4.53.6 source (checked 3 Nov 2026). "Not published" means the brand page we checked doesn't list it, so we leave it blank rather than guess.
All the differences
- Case size: the Hamilton Khaki Aviation Pilot Day Date Auto H64615735 is 2 mm larger (42 mm vs 40 mm).
- Thickness: the Longines Spirit L3.810.4.53.6 is 0.35 mm thicker (12.2 mm vs 11.85 mm).
- Power reserve: the Hamilton Khaki Aviation Pilot Day Date Auto H64615735 is 8 hours longer (80 h vs 72 h).
- Price: the Hamilton Khaki Aviation Pilot Day Date Auto H64615735 lists for $1,475 less in the US ($1,075 vs $2,550).
- Calibre: Hamilton Khaki Aviation Pilot Day Date Auto H64615735 has H-40; Longines Spirit L3.810.4.53.6 has L888.4.
- Lug width: Hamilton Khaki Aviation Pilot Day Date Auto H64615735 has 20 mm; Longines Spirit L3.810.4.53.6 has 21 mm.
Wrist fit
Lug-to-lug decides overhang more than diameter does. Enter your wrist to see how each one should wear.
- Hamilton Khaki Aviation Pilot Day Date Auto H64615735 –
- Longines Spirit L3.810.4.53.6 –
Same rule of thumb as Watch Finder: case diameter of about 23.5% of your wrist circumference (−2 mm to +2.5 mm), and lug-to-lug no longer than about 29% of it plus 1 mm. A guide, not a rule; flat or round wrists differ.
Strap fit
The Hamilton Khaki Aviation Pilot Day Date Auto H64615735 has 20 mm lugs. The Longines Spirit L3.810.4.53.6 has 21 mm lugs. A strap bought for one won't fit the other. Size charts: Hamilton lug width chart · Longines lug width chart.
Which should you buy?
It is the more compact case on paper (42 mm across). Our sizing guide puts it at about 16.8–18.7 cm.
It has the lower US list price, $1,075, a $1,475 difference.
It has the longer published power reserve: 80 h.
Prices and where to buy
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More: All Hamilton Khaki Aviation references · All Longines Spirit references.
Questions
Which is bigger, the Hamilton Khaki Aviation Pilot Day Date Auto H64615735 or the Longines Spirit L3.810.4.53.6?
Per the brands, the Hamilton Khaki Aviation Pilot Day Date Auto H64615735 is 42 mm across and the Longines Spirit L3.810.4.53.6 is 40 mm.
Which is cheaper?
The Hamilton Khaki Aviation Pilot Day Date Auto H64615735, at a US list price of $1,075 vs $2,550 when we checked.
Which is more water-resistant?
Hamilton Khaki Aviation Pilot Day Date Auto H64615735: 100 m. Longines Spirit L3.810.4.53.6: 100 m.
Have you tested these watches?
No. This comparison uses brand-published specs and our own analysis of them, not hands-on testing.
Watch.co is independent and not affiliated with any brand. We haven't handled these watches for this page: everything here comes from brand-published specs and our own analysis. Brand names are used only to identify products.