Japan Original TMI NH71 NH72 NH70 Movement High Accuracy Skeletonized Automatic 24 jewels Modification Parts

The Seiko NH70, NH71, and NH72 are skeletonised automatic movements manufactured by Seiko Instruments Inc. (SII) / Time Module Inc. (TMI). They belong to the NH7X family, built upon the proven and robust NH35 base calibre. These movements are popular among microbrands and the modding community for their reliability, ease of service, and distinctive open-worked design that showcases the mainspring barrel and balance wheel.

The three calibres share identical mechanical specifications and functionality. Their only differences lie in the decorative finish and colour:

• NH70 – Silver (nickel‑plated) skeleton movement, no date.

• NH71 – Gold‑plated skeleton movement, no date.

• NH72 – Ruthenium‑grey (dark grey) skeleton movement, no date.

All three are non‑date movements (no calendar complication) and feature a cut‑out design that gives a clear view of the movement’s internal operation.

Specification List