What is a Seiko mod?
A Seiko Mod is a custom-built timepiece made by modifying a genuine Seiko movement watch with upgraded, hand-selected components from aftermarket suppliers. At Circa Watch Labs, we specialize in designing and assembling these unique watches from the ground up — blending precision craftsmanship with personalized style.
Our Seiko Mods are powered by trusted Seiko TMI movements, including both automatic and meca-quartz chronograph calibers, such as the NH35, NH34, NH38, NH71, and VK63/VK64:
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NH35: A robust, time-only automatic movement known for its accuracy and reliability.
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NH34: Adds a GMT function, perfect for tracking multiple time zones.
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NH38: A no-date version for a clean, balanced dial layout.
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NH71: An open-heart movement that showcases the internal mechanics through the dial.
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VK63 / VK64: Meca-quartz chronograph movements that combine quartz accuracy with a mechanical-style chronograph sweep and tactile feel, perfect for those who love stopwatch functionality with a classic look.
The NH series automatic movements are self-winding, powered by the motion of your wrist, and offer a reliable 41-hour power reserve. Meanwhile, the VK series meca-quartz options provide battery-powered precision with the look and feel of a mechanical chronograph — delivering the best of both worlds.
We use only high-quality materials, including 316L or 904L stainless steel cases for superior durability and corrosion resistance, and sapphire crystal for top-tier scratch resistance and clarity. Each build is fully customizable — from the bezel and hands to the dial, case finish, and strap. We also offer dials from premium suppliers with options for custom logos and finishes, giving your watch a uniquely personal touch.
Whether you're a seasoned watch enthusiast or purchasing your first custom timepiece, Seiko Mods offer a rare opportunity to own something that’s both technically excellent and uniquely yours.
In essence, a Seiko Mod is more than just a watch — it’s a handcrafted, wearable statement piece designed to stand out and built to last.