Seiko Nautilus Open Heart Automatic 40mm – Green
Seiko Nautilus Open Heart Automatic 40mm – Green
- Buy more and get discounts
- In stock, ready to ship
Couldn't load pickup availability
Authenticity Guaranteed
Authenticity Guaranteed
Authenticity lies at the heart of our business, and every product we offer is carefully reviewed by our expert team.
Our specialists are among the industry’s most experienced and thoroughly trained. We also source all products exclusively from reliable, trusted suppliers.
Shipping, Delivery & Exchanges
Shipping, Delivery & Exchanges
Enjoy free shipping on all orders, with fast and secure tracked delivery.
- Free Shipping on All Orders
- Estimated Delivery: 5–12 Business Days
- Fast & Secure Tracked Shipping
Every order is carefully prepared and shipped with trusted carriers to ensure a smooth and reliable delivery experience.
Not completely satisfied with your purchase? You may return or exchange any eligible, full-priced item within 14 days of delivery.
Final sale items are not eligible for returns or exchanges and will be clearly identified on the product page. Please review our Return Policy for full details.
DESCRIPTION
Watches — watch
Seiko Nautilus Open Heart Automatic 40mm – Green
A sapphire crystal, a strap matched to the dial, and a wrist movement that does the winding for you.

Green Strap
The strap is tied to the dial rather than set against it, so the whole watch reads as one object.
Mechanical Character
It is mechanical rather than electronic, so it answers to your motion and nothing else.
40 mm case
At 40 mm it reads as a classic size, equally at home with a cuff and a rolled sleeve.
What sapphire and a matched strap buy
Sapphire is the part that decides whether the watch still looks new in three years, because the face takes every graze a hand collects. A strap cut to the dial does something quieter: it stops the eye from breaking the watch into parts. At 40 mm the whole thing sits where a watch is supposed to sit.
The mechanical read other people make
Mechanical watches carry a particular signal: somebody chose to be involved. At close range the matched strap and the clear crystal make it look deliberate rather than grabbed in a hurry, and that is what gets filed about you. Nobody has to say a word for it to land.
What specs never quite say
The pull of something that keeps going
There is an odd attachment to a watch that runs because you wore it. You put it on and you are part of why it works.
Leave it off and it slows to a stop, which is the only reminder you will ever need that it is doing something.
What you are getting
- Strap
- Green Strap
- Movement
- Mechanical Character
- Case size
- 40 mm
- Crystal
- Sapphire crystal
Why it costs what it costs
We hold this stock ourselves and send it out from our own shelves. No boutique floor to pay for, nobody taking a cut in between — one step from our rack to your door instead of four. The piece is not cheaper; the route is shorter.
Store offer
Two pieces get you a cap. Three get you a cap and a wallet.
It runs across the whole store, so the pieces do not have to match.
- Any two items — a cap goes in the box, free.
- Any three or more — the cap plus a wallet.
About the size of this lot
There was one small batch of this dial, and a restock is not guaranteed — the strap tone alone never repeats exactly.
Pick yours above.

Italian Heritage Since 1975
Founded in Italy in 1975, Arkon began as a family business driven by a passion for timeless men’s fashion and refined craftsmanship. What started as a small Italian house has grown into a recognized name in contemporary luxury, bringing together tradition, sophistication, and modern design.
Today, Arkon carries its heritage forward, creating a vision of menswear for those who believe true style is timeless.