---
description: "Genuine Seiko NH35/NH36/NH37/NH38/NH39 first reduction wheel #0511010. Automatic winding part. Made in Japan. Professional repair."
title: "SEIKO (SII) NH35/NH36/NH37/NH38/NH39 First Reduction Wheel #0511010 - Sofly"
image: https://www.soflypart.com/wp-content/uploads/2019/05/NH36SLUN.jpg
---
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- **SEIKO (SII) NH35/NH36/NH37/NH38/NH39 First Reduction Wheel #0511010**
[](https://www.soflypart.com/wp-content/uploads/2019/05/NH36SLUN.jpg)
# SEIKO (SII) NH35/NH36/NH37/NH38/NH39 First Reduction Wheel #0511010
$2.00
You Saved
| Brand | Choose an option SEIKO- 
Clear |
| --- | --- |
### Discount
| Quantity | Discount (%) | Price |
| --- | --- | --- |
| 1 - 2 | — | $2.00 |
| 3 - 4 | 5% | $1.90 |
| 5 - 9 | 7% | $1.86 |
| 10 - 14 | 10% | $1.80 |
| 15+ | 15% | $1.70 |
### Discount
| Quantity | Discount (%) | Price |
| --- | --- | --- |
| 1 - 2 | — | $2.00 |
| 3 - 4 | 5% | $1.90 |
| 5 - 9 | 7% | $1.86 |
| 10 - 14 | 10% | $1.80 |
| 15+ | 15% | $1.70 |
SEIKO (SII) NH35/NH36/NH37/NH38/NH39 First Reduction Wheel #0511010 quantity
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- Covers 99% of Repair Needs
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## Product Description
This is a **genuine Seiko (SII) first reduction wheel** (part #0511010), an original Japanese-made component for the popular NH35, NH36, NH37, NH38, and NH39 automatic movements. As a critical part of the automatic winding system, this gear transfers rotational energy from the oscillating weight to the mainspring barrel, ensuring efficient power generation.
This brand new original part is essential for watchmakers restoring proper automatic winding function when the original wheel becomes worn or damaged.
## Features & Function
- **Sapphire Crystal** – Mohs 9, highly scratch-resistant and optically clear.
- **Pan-Shaped Domed Profile** – Faithfully replicates the iconic aviation‑instrument curved crystal.
- **Precise Dimensions** – 35.0mm diameter, 3.4mm height – exact fit for the 40mm Pilot case.
- **Generic Aftermarket** – Non-original but manufactured to OEM specs for direct replacement.
- **Cost-Effective** – Affordable alternative for repair or restoration.
## Specifications
| Parameter | Details |
| --- | --- |
| Compatible Model | Zenith Pilot Type 20 Extra Special 11.1940.679 |
| Type | Generic aftermarket |
| Material | Synthetic sapphire |
| Shape | Pan-shaped (domed) |
| Diameter | 35.0 mm |
| Height | 3.4 mm |
## Applications
- Zenith Pilot Type 20 Extra Special 11.1940.679 (40mm steel case, vintage pilot watch)
- Other Pilot series models using the same 35.0mm domed crystal (verify original size)
- Replacement of damaged, deeply scratched, or aged original crystals
- Maintaining the unique aviation‑instrument look
## Frequently Asked Questions
**1. Is this a genuine Zenith crystal?**
No. It is a generic aftermarket replacement, not original, but matches the 11.1940.679 dimensions.
**2. Does this crystal fit other Pilot models (e.g., 29.2430.679)?**
Different Pilot references have different case and crystal sizes (e.g., 45mm cases use larger crystals). Measure your original crystal diameter and height – should be 35mm/3.4mm.
**3. What should I pay attention to during installation?**
The pan-shaped crystal has a specific orientation – dome facing outward. Use a new gasket and UV adhesive, press evenly with a crystal press. Professional installation is recommended.
**4. Will the original water resistance be maintained?**
Pilot Type 20 is typically 50-100m water resistant. Proper installation with a new gasket can restore similar resistance. A water resistance test is advised.
**5. Is a gasket included?**
Usually not. The sealing gasket must be purchased separately. Confirm with the seller.
## Why Choose SOFLY Watch Parts?
- Fast worldwide shipping within 3 business days.
- Competitive pricing on Seiko/Hattori calibers.
- 3,000+ watch movements and parts in stock.
- Trusted by watchmakers worldwide.
- Personalized sourcing support via **info@soflypart.com** or WhatsApp **+86 18620212114**.
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As a critical part of the automatic winding system, this gear transfers rotational energy from the oscillating weight to the mainspring barrel, ensuring efficient power generation. This brand new original part is essential for watchmakers restoring proper automatic winding function when the original wheel becomes worn or damaged. Features & Function Sapphire Crystal\u00a0\u2013 Mohs 9, highly scratch-resistant and optically clear. Pan-Shaped Domed Profile\u00a0\u2013 Faithfully replicates the iconic aviation\u2011instrument curved crystal. Precise Dimensions\u00a0\u2013 35.0mm diameter, 3.4mm height \u2013 exact fit for the 40mm Pilot case. Generic Aftermarket\u00a0\u2013 Non-original but manufactured to OEM specs for direct replacement. Cost-Effective\u00a0\u2013 Affordable alternative for repair or restoration. Specifications Parameter Details Compatible Model Zenith Pilot Type 20 Extra Special 11.1940.679 Type Generic aftermarket Material Synthetic sapphire Shape Pan-shaped (domed) Diameter 35.0 mm Height 3.4 mm Applications Zenith Pilot Type 20 Extra Special 11.1940.679 (40mm steel case, vintage pilot watch) Other Pilot series models using the same 35.0mm domed crystal (verify original size) Replacement of damaged, deeply scratched, or aged original crystals Maintaining the unique aviation\u2011instrument look Frequently Asked Questions 1. Is this a genuine Zenith crystal? No. It is a generic aftermarket replacement, not original, but matches the 11.1940.679 dimensions. 2. Does this crystal fit other Pilot models (e.g., 29.2430.679)? Different Pilot references have different case and crystal sizes (e.g., 45mm cases use larger crystals). Measure your original crystal diameter and height \u2013 should be 35mm/3.4mm. 3. What should I pay attention to during installation? The pan-shaped crystal has a specific orientation \u2013 dome facing outward. Use a new gasket and UV adhesive, press evenly with a crystal press. Professional installation is recommended. 4. Will the original water resistance be maintained? Pilot Type 20 is typically 50-100m water resistant. Proper installation with a new gasket can restore similar resistance. A water resistance test is advised. 5. Is a gasket included? Usually not. The sealing gasket must be purchased separately. Confirm with the seller. Why Choose SOFLY Watch Parts? Fast worldwide shipping within 3 business days. Competitive pricing on Seiko/Hattori calibers. 3,000+ watch movements and parts in stock. Trusted by watchmakers worldwide. 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Precise Dimensions\u00a0\u2013 35.0mm diameter, 3.4mm height \u2013 exact fit for the 40mm Pilot case. Generic Aftermarket\u00a0\u2013 Non-original but manufactured to OEM specs for direct replacement. Cost-Effective\u00a0\u2013 Affordable alternative for repair or restoration. Specifications Parameter Details Compatible Model Zenith Pilot Type 20 Extra Special 11.1940.679 Type Generic aftermarket Material Synthetic sapphire Shape Pan-shaped (domed) Diameter 35.0 mm Height 3.4 mm Applications Zenith Pilot Type 20 Extra Special 11.1940.679 (40mm steel case, vintage pilot watch) Other Pilot series models using the same 35.0mm domed crystal (verify original size) Replacement of damaged, deeply scratched, or aged original crystals Maintaining the unique aviation\u2011instrument look Frequently Asked Questions 1. Is this a genuine Zenith crystal? No. It is a generic aftermarket replacement, not original, but matches the 11.1940.679 dimensions. 2. Does this crystal fit other Pilot models (e.g., 29.2430.679)? Different Pilot references have different case and crystal sizes (e.g., 45mm cases use larger crystals). Measure your original crystal diameter and height \u2013 should be 35mm/3.4mm. 3. What should I pay attention to during installation? The pan-shaped crystal has a specific orientation \u2013 dome facing outward. Use a new gasket and UV adhesive, press evenly with a crystal press. Professional installation is recommended. 4. Will the original water resistance be maintained? Pilot Type 20 is typically 50-100m water resistant. Proper installation with a new gasket can restore similar resistance. A water resistance test is advised. 5. Is a gasket included? Usually not. The sealing gasket must be purchased separately. Confirm with the seller. Why Choose SOFLY Watch Parts? Fast worldwide shipping within 3 business days. Competitive pricing on Seiko/Hattori calibers. 3,000+ watch movements and parts in stock. 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