The Men's Open-Heart Automatic Watch from Smith Watches is a 40 mm mechanical timepiece with a cut-out dial at 9 o'clock that exposes the beating balance wheel, a 316L stainless steel case, and a stainless steel bracelet. Self-winding automatic movement, approx. 40-hour power reserve, 3 ATM water-resistant, 2-year warranty.
What is an open-heart watch?
An open-heart watch is a mechanical watch with a small cut-out in the dial that exposes the balance wheel — the oscillating part of the movement that gives a mechanical watch its rhythm. Unlike a full skeleton, the rest of the face stays intact, keeping the time legible. Our opening is at 9 o'clock, a classic mid-20th-century layout.
How does the automatic movement work?
Inside the watch, a rotor spins freely on the motion of your wrist. As it spins, it winds the mainspring, which powers the gear train and the balance wheel. No battery, no manual winding required when worn daily. Power reserve is approximately 40 hours off the wrist.
Key features
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Open-heart dial cut-out at 9 o'clock, exposing the oscillating balance wheel.
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Automatic self-winding movement, approx. 40-hour power reserve.
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40 mm 316L stainless steel case, versatile diameter for dress and casual.
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Exhibition case back showing the full movement and rotor.
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Four colour combinations: silver/black, gold/black, gold/white, silver/white.
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Scratch-resistant mineral crystal, front and back.
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Stainless steel bracelet with deployant clasp, 20 mm lug width.
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Water resistance: 3 ATM.
Specifications
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Case diameter: 40 mm
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Case thickness: 12 mm
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Case material: 316L stainless steel
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Dial: Open-heart at 9 o'clock (black or white)
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Movement: Automatic, self-winding, approx. 40-hour power reserve
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Crystal: Mineral, front and back
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Bracelet: Stainless steel, 20 mm lug width
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Water resistance: 3 ATM (30 metres)
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Warranty: 2 years, international
Who is this watch for?
A first mechanical watch for men moving up from quartz, or a second watch for collectors who want a 40 mm automatic. The balance-wheel cut-out is a conversation piece without being flashy. The 40 mm case is the safest size for most wrists (6"–8.5").
What's included in the box
- One Men's Open-Heart Automatic Watch 40mm Stainless Steel
- Smith Watches gift box
- Owner's guide
- 2-year international warranty card
Frequently asked questions
Do automatic watches need batteries?
No. Automatic movements are wound by wrist motion. Worn daily, they stay running continuously. If unworn for more than about 40 hours, the watch will stop and can be restarted by shaking or winding the crown manually.
How is the accuracy compared to a quartz watch?
Mechanical movements typically run within -20 to +40 seconds per day. Quartz is more accurate, but mechanical watches have character — you feel the oscillation and can watch the balance wheel work.
Will it fit a smaller wrist?
At 40 mm, yes. The most versatile diameter, suits wrists from 6" to 8.5". If you usually wear 38–42 mm watches, this will feel right.
Can I see the movement through the back?
Yes. The case back is a clear mineral crystal showing the full automatic movement and the rotor in motion. This is called an exhibition case back, standard on mechanical watches.
Is the steel bracelet sized to my wrist?
The bracelet ships at full factory length to fit wrists up to 8.5". For smaller wrists, any local jeweller can remove links in a few minutes for a small fee ($5–$15).
Shipping, warranty, and returns
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Free tracked shipping on every order, no minimum spend.
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Fulfillment and delivery Orders are fulfilled from our United States warehouse in Torrance, California. Orders are typically processed within 2-3 business days, and total delivery is usually 7-15 business days depending on destination.
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2-year Smith warranty covering movement and manufacturing defects.
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30-day returns for eligible unused items. Return shipping is covered for defective, damaged, or incorrect items.
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Customer support at support@smith-official.com. We reply within one business day.
For company information and legal details, see our Imprint & Legal page.
