SEIKOJUST black diamond

The SEIKOJUST black diamond reinterprets the codes of the great classic dress-sport watches: a glossy black dial, refined applied indices and an elegant case that outlasts every trend. Its diamond-style set markers catch the light with every movement of the wrist, for a resolutely precious look. A versatile watch, equally at home with a suit or in everyday life.

Hand-assembled in France around a genuine Seiko automatic movement, it combines the reliability of proven Japanese engineering with the freedom of a fully customised piece. Every watch is regulated and tested before shipping.

Technical specifications:

• Genuine Seiko NH35 automatic movement
• 316L stainless steel case, 36mm or 39mm (excl. crown)
• 20mm lug width, bracelet adjustable with the included sizing kit
• Sapphire crystal, sapphire case back
• Date display
• Choice of bracelet: Oyster or Jubilee in 316L steel
• Screw-down crown and case back
• Water resistance: splash-resistant — two reinforced options: 5 ATM (50 m) or 10 ATM (100 m) for bathing and swimming (excl. diving)

Fully customisable — case size, dial colour, bracelet type, custom logo or image engraved. Build your own SEIKOJUST via our configurator.

Delivered with storage box and sizing kit. 2-year warranty. Lead time: approx. 2 weeks made to order.

Custom creation by Time2Seiko — not affiliated with the Seiko brand.

All our watches handle splashes, rain and hand washing. That's enough for normal everyday use.

At checkout, you can enhance that water resistance:

• 5 ATM (50 m) — shower, washing up, heavy rain. Not for swimming.

• 10 ATM (100 m) — pool, sea, snorkelling: you can swim. Not for scuba diving. Available on SEIKOJUST, SEIKODATE, SEIKOMARINER and SEIKO GMT.

ATM stands for atmosphere: 1 ATM is the pressure of a 10-metre column of water, measured in laboratory conditions. These figures shouldn't be taken literally, as moving your arm through water generates far higher pressure. Our usage recommendations are therefore deliberately more cautious than the numbers suggest.

Important: the crown must be fully screwed down before any contact with water. It is the only real entry point for water on a watch. For that reason, our 2-year warranty does not cover water resistance: we cannot guarantee a step we don't perform on your behalf. It does, however, cover any manufacturing or assembly defect.

Which size to choose: 36mm or 39mm?

Our SEIKOJUST cases come in two diameters to suit every wrist:

• 39mm: The reference size, versatile and unisex. Ideal for wrists from 16 cm to 20 cm. Our recommended size for a look that is both classic and sporty.
• 36mm: A more discreet and elegant size, perfect for slim wrists from 14 cm to 17.5 cm. Highly favored for a feminine fit or a vintage / dressy style.

How to measure your wrist?

Wrap a tape measure (or a piece of string that you then lay against a ruler) around your wrist, just above the bone. Note the circumference in centimeters and choose your size accordingly.

Adjustable bracelet included 🔧

No need to worry about length: every watch ships with an adjustment kit that lets you remove links and fit the bracelet perfectly to your wrist. Sizing takes just a few minutes, with no watchmaking experience required, thanks to the small tool included in the box.

A question about choosing your size? Contact us, we will be happy to guide you.

This model is made to order, can be customized to your taste, and will be delivered within approximately 2 weeks.

Delivered with a storage box and spare links.

🚚 Free shipping worldwide.

All our watches are covered by a 2-year warranty against manufacturing defects, starting from the date of purchase. This warranty covers exclusively material and manufacturing defects. It does not apply to damage resulting from misuse, accident, normal wear, or modification carried out by an unauthorized third party.

To make a warranty claim, you must provide proof of purchase and contact our customer service within 14 days of discovering the defect. Shipping costs related to warranty repairs remain the responsibility of the customer.

We give you 30 days from receipt of your order to change your mind. You can return your watch and be fully refunded, provided that:

• The watch is returned in its original, unworn condition
• It is accompanied by its original packaging and accessories
• It shows no damage or signs of wear

To initiate a return, contact us by email with your order number. Return shipping costs are the responsibility of the customer.

1. Are your watches under warranty?

Yes, all our Seiko mod watches are covered by a 2-year warranty against manufacturing and material defects, starting from the date of purchase. If something goes wrong, we are here to fix it.

The warranty covers material and assembly defects. It does not apply to damage caused by misuse, accident, normal wear, or modification carried out by a third party.

To activate the warranty, contact us with your proof of purchase within 14 days of noticing the defect. Return shipping costs are the responsibility of the customer.

2. Are the watches water-resistant?

By default, all our watches resist splashes and hand washing, water resistance sufficient for normal everyday use. We recommend removing the watch before showering or swimming.

If you would like enhanced protection, we offer a 5 ATM water resistance option available at checkout for an additional 14.99€. It allows you to wear your watch in the shower and during light water activities, provided the crown is properly screwed down into the case.

3. What types of modifications do you offer for Seiko watches?

Our Seiko mods are fully customizable from A to Z: case, dial, hand color, bracelet type (Oyster steel, Jubilee, rubber, or silicone), bezel, and even your logo or an image engraved on the dial, a service very few makers offer.

Everything is created directly on our online configurator, or through discussion with us by email or Instagram for more complex projects.

4. How can I be sure of the quality of your work?

Every Seiko mod watch is hand-assembled in France, with authentic Seiko movements and premium components selected one by one. Each piece is regulated and inspected before shipping.

We also provide responsive customer service: if you have any questions before, during, or after your order, we are reachable by email and on Instagram. 2-year warranty included on all watches.

5. How can I customize my watch?

You have two options to customize your watch:

– Use our online configurator to create your made-to-measure watch from A to Z: case, dial, hands, bracelet, engraving, logo… Let your imagination run free!

– Or, choose a watch already offered on our site, and at checkout, let us know in the payment instructions which modifications you would like.

You can also contact us directly by email or via Instagram: together we will design the ideal watch, to your taste.

👉 Go to the configurator

6. How long does it take to receive my watch?

Every watch is made to order, specifically for you, in France. Allow about 2 weeks between your order and shipping, the time needed to assemble, regulate, and inspect your unique piece.

Once shipped, you will receive a tracking email with the parcel number. We ship within France and worldwide.