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Outbyte PC Repair FREEClear out junk files and repair common Windows errorsFree Scan →Outbyte Driver Updater FREEScan for outdated or missing drivers - takes under a minuteDriver Scan →The Hamilton Jazzmaster Open Heart H32705501 pairs an automatic movement with a partial view of its mechanism, but its 42 mm case and 50 mm lug-to-lug length deserve as much attention as its dial design. Hamilton lists an 80-hour power reserve and 5 bar (50 m) water resistance. This review focuses on that specific US-listed reference, not every watch in the Jazzmaster Open Heart family.
Which Jazzmaster Open Heart does this review cover?
The reference is H32705501, the 42 mm Jazzmaster Open Heart Auto listed on Hamilton’s US product page. Hamilton describes its dial as smoky brown, while the specification table calls the color champagne; those are the manufacturer’s two descriptions, not a standardized color match.
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Other Jazzmaster Open Heart references differ in size, dial color, and strap or bracelet configuration. Hamilton’s brochure includes the earlier 42 mm H32705521, while a T3 report dated March 6, 2026 describes a wider family with 36, 40, and 42 mm sizes. Check the reference number and current regional listing before applying any specification or price to another version.
What does the open-heart design show?
An aperture in the dial exposes part of the movement; it is not a fully skeletonized dial. Hamilton also lists an open case back, giving a separate view of the movement from the rear. The design makes the mechanism a visible feature while leaving much of the dial intact.
#1 Best Overall
- AUTOMATIC MOVEMENT: Swiss H-10 movement with 80-hour reserve ensures consistent performance. Experience precision that matches both daily tasks and adventures, a testament to Swiss craftsmanship in automatic timekeeping.
- WATER RESISTANT TO 50M: Withstands 5 bar (50 meters), ideal for swimming and outdoor pursuits. Perfect for those who demand resilient accessories that accompany them confidently on their explorative journeys.
- CONTEMPORARY SOPHISTICATION: Featuring a 40mm stainless steel case and a sleek blue dial, this modern watch combines heritage with minimalist design. Complete with sapphire crystal , it’s the perfect expression of style and quality.
- PREMIUM MATERIALS: Leather strap with pin buckle offers day-long comfort. The clean lines and sophisticated design make it the perfect accessory for both casual wear and formal attire, merging functionality with fashion.
- RICH HERITAGE: Over a century of Hamilton's legacy in field watches, admired for precision. Originally designed for WWI soldiers, these timepieces combine rugged durability with history, showcasing Hamilton's commitment to quality and innovation.
Movement and power reserve
Hamilton specifies its automatic H-10 caliber, a three-hand movement, with an 80-hour power reserve and a Nivachron balance spring. Hamilton describes H-10 as “A three-hand movement with or without a date function and boasting a superior power reserve of 80 hours, the H-10 appears with intricate contrasting snail and pearled patterns for the American Classic models it drives and streamlined surfaces for the pilots’ watches.” The quote is Hamilton’s general description of the caliber; it does not establish independently measured accuracy for this watch.
The 80-hour figure is Hamilton’s published reserve, not a timing-test result. An automatic watch runs as it is worn and wound; if left unworn long enough, it will stop and need to be wound and set again.
Rank #2
- AUTOMATIC MOVEMENT: Swiss H-10 movement with 80-hour reserve ensures consistent performance. Experience precision that matches both daily tasks and adventures, a testament to Swiss craftsmanship in automatic timekeeping.
- WATER RESISTANT TO 50M: Withstands 5 bar (50 meters), ideal for outdoor pursuits. Perfect for those who demand resilient accessories that accompany them confidently on their explorative journeys.
- CLEAR AND TIMELESS DESIGN: 42mm stainless steel case with a refined dial and an elegant stainless steel bracelet. Equipped with sapphire crystal and classic detailing, it blends vintage charm with modern functionality for any occasion.
- PREMIUM MATERIALS: Stainless steel bracelet with folding clasp offers day-long comfort. The clean lines and sophisticated design make it the perfect accessory for both casual wear and formal attire, merging functionality with fashion.
- RICH HERITAGE: Over a century of Hamilton's legacy in field watches, admired for precision. Originally designed for WWI soldiers, these timepieces combine rugged durability with history, showcasing Hamilton's commitment to quality and innovation.
Case dimensions and strap
| Specification | Hamilton H32705501 |
|---|---|
| Case diameter | 42 mm |
| Lug-to-lug | 50 mm |
| Thickness | 11.4 mm |
| Lug width | 22 mm |
| Case and crystal | Stainless steel; sapphire crystal with anti-reflective treatment |
| Supplied strap | Brown calf leather, strap reference H6000002301, with pin buckle |
The 50 mm lug-to-lug measurement can be more useful than diameter when judging how much of the wrist a watch spans, but no single dimension predicts fit for every wrist. If possible, try this reference on; otherwise, compare its lug-to-lug length and thickness with a watch you already know fits. A replacement strap should match the 22 mm lug width, and its buckle and attachment must also be compatible.
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Water resistance and everyday use
Hamilton rates this model at 5 bar (50 m). Treat that as the manufacturer’s stated water-resistance rating, not a promise that the watch is suitable for every activity involving water. Match use to Hamilton’s guidance for the specific watch and avoid assuming a depth figure alone covers a particular activity.
Rank #3
- AUTOMATIC MOVEMENT: Swiss H-10 movement with 80-hour reserve ensures consistent performance. Experience precision that matches both daily tasks and adventures, a testament to Swiss craftsmanship in automatic timekeeping.
- WATER RESISTANT TO 50M: Withstands 5 bar (50 meters), ideal for swimming and outdoor pursuits. Perfect for those who demand resilient accessories that accompany them confidently on their explorative journeys.
- CONTEMPORARY SOPHISTICATION: Featuring a 42mm stainless steel case and a sleek black dial, this modern watch combines heritage with minimalist design. Complete with sapphire crystal , it’s the perfect expression of style and quality.
- PREMIUM MATERIALS: Leather strap with folding clasp offers day-long comfort. The clean lines and sophisticated design make it the perfect accessory for both casual wear and formal attire, merging functionality with fashion.
- RICH HERITAGE: Over a century of Hamilton's legacy in field watches, admired for precision. Originally designed for WWI soldiers, these timepieces combine rugged durability with history, showcasing Hamilton's commitment to quality and innovation.
The sapphire crystal, anti-reflective treatment, and Super-LumiNova are also among Hamilton’s published specifications. They describe materials and features, not independent assessments of scratch resistance, legibility, or performance over time.
Is it a good first automatic watch?
It may suit a first-time automatic buyer who specifically wants a visible movement, prefers a leather-strap configuration, and is comfortable with the stated dimensions. The open-heart aperture gives the watch a more mechanical look than a conventional closed dial, while the automatic H-10 and published 80-hour reserve are the core movement details to weigh.
Rank #4
- AUTOMATIC MOVEMENT: Swiss H-10 movement with 80-hour reserve ensures consistent performance. Experience precision that matches both daily tasks and adventures, a testament to Swiss craftsmanship in automatic timekeeping.
- WATER RESISTANT TO 50M: Withstands 5 bar (50 meters), ideal for swimming and outdoor pursuits. Perfect for those who demand resilient accessories that accompany them confidently on their explorative journeys.
- CONTEMPORARY SOPHISTICATION: Featuring a 42mm stainless steel case and a sleek beige dial, this modern watch combines heritage with minimalist design. Complete with sapphire crystal , it’s the perfect expression of style and quality.
- PREMIUM MATERIALS: Leather strap with folding clasp offers day-long comfort. The clean lines and sophisticated design make it the perfect accessory for both casual wear and formal attire, merging functionality with fashion.
- RICH HERITAGE: Over a century of Hamilton's legacy in field watches, admired for precision. Originally designed for WWI soldiers, these timepieces combine rugged durability with history, showcasing Hamilton's commitment to quality and innovation.
It is less straightforward if a smaller case is a priority, if you want a fully skeletonized dial, or if your intended water use calls for a different rating. A first automatic is also a different ownership experience from a battery-powered watch: it may need setting after it stops, and this specification page does not provide an independent accuracy result.
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Hamilton’s US page showed a price of $1,245 and in-stock status in the 2026 listing used for this article. Price and stock can change, and that US listing should not be treated as a current price or availability guarantee in another country. For family-level UK context, T3 reported prices beginning at £990 on March 6, 2026; that figure is not a price for every reference or market.
Quick Recap
Best Value
- AUTOMATIC MOVEMENT: Swiss H-10 movement with 80-hour reserve ensures consistent performance. Experience precision that matches both daily tasks and adventures, a testament to Swiss craftsmanship in automatic timekeeping.
- WATER RESISTANT TO 50M: Withstands 5 bar (50 meters), ideal for outdoor pursuits. Perfect for those who demand resilient accessories that accompany them confidently on their explorative journeys.
- CLEAR AND TIMELESS DESIGN: 42mm stainless steel case with a refined dial and an elegant leather strap. Equipped with sapphire crystal and classic detailing, it blends vintage charm with modern functionality for any occasion.
- PREMIUM MATERIALS: Leather strap with pin buckle offers day-long comfort. The clean lines and sophisticated design make it the perfect accessory for both casual wear and formal attire, merging functionality with fashion.
- RICH HERITAGE: Over a century of Hamilton's legacy in field watches, admired for precision. Originally designed for WWI soldiers, these timepieces combine rugged durability with history, showcasing Hamilton's commitment to quality and innovation.
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply.
