Time Module · commonly listed as Seiko NH35
NH35A
The everyday automatic.
- Power reserve
- More than 41 h
- Beat rate
- 3 Hz · 21,600 bph
- Functions
- Date
The Watch Resource · Caliber library
Know what
makes it tick.
The same movement can live inside very different watches. Get to know the caliber, understand the numbers, and find the watches that use it.
A matter of millimeters
Browse by movement maker
Different ways to keep time.
From a simple three-hander to a second time zone.
Explore 6 calibers, grouped by their maker.
TMI
2 calibersTime Module · independently adjustable GMT hand
NH34A
One watch. A second time zone.
- Power reserve
- More than 41 h
- Beat rate
- 3 Hz · 21,600 bph
- Functions
- GMT + date
Sellita
2 calibersSwiss automatic · check the grade
SW200-1
One name. Different executions.
- Power reserve
- 38 h min. · 41 h typical
- Beat rate
- 4 Hz · 28,800 bph
- Functions
- Date
Slim Swiss automatic · date and no-date executions
SW300-1
More room for a slimmer watch.
- Power reserve
- 50 h min. · 56 h typical
- Beat rate
- 4 Hz · 28,800 bph
- Functions
- Date / no-date variants
Miyota
2 calibers90 series · three hands, no date
9039
Less calendar. More simplicity.
- Power reserve
- Approx. 42 h
- Beat rate
- 4 Hz · 28,800 bph
- Functions
- No date
90 series · three hands and a date
9015
A slim movement. A useful date.
- Power reserve
- Approx. 42 h
- Beat rate
- 4 Hz · 28,800 bph
- Functions
- Date
The essentials, side by side
Small differences.
Everyday consequences.
Scroll across to compare all 6 calibers.
Read the individual guides for sources and context.
| Specification | TMINH35A | TMINH34A | SellitaSW200-1 | SellitaSW300-1 | Miyota9039 | Miyota9015 |
|---|---|---|---|---|---|---|
| Power reserve | More than 41 h | More than 41 h | 38 h min. · 41 h typical | 50 h min. · 56 h typical | Approx. 42 h | Approx. 42 h |
| Frequency | 3 Hz · 21,600 bph | 3 Hz · 21,600 bph | 4 Hz · 28,800 bph | 4 Hz · 28,800 bph | 4 Hz · 28,800 bph | 4 Hz · 28,800 bph |
| Published accuracy | −20 / +40 s/day | −20 / +40 s/day | Depends on grade | Depends on grade | −10 / +30 s/day | −10 / +30 s/day |
| Movement height | 5.32 mm | 5.32 mm | 4.60 mm | 3.60 mm | 3.90 mm | 3.90 mm |
| Outside diameter | 27.40 mm | 27.40 mm | 26.00 mm | 26.20 mm | 26.00 mm | 26.00 mm |
| Jewels | 24 | 24 | 26 | 25 | 24 | 24 |
| Calendar | Date | Date | Date | Date / no-date variants | No date | Date |
| Second time zone | — | Caller GMT · 24-hour hand | — | — | — | — |
| Hand winding / hacking | Yes / yes | Yes / yes | Yes / yes | Yes / yes | Yes / yes | Yes / yes |
Reserve figures assume a full wind. Published rate figures use manufacturer test conditions and are not a head-to-head test. Outside diameter is different from case-fitting diameter; each guide explains the distinction. SW300-1 reserve figures describe the current documentation; older versions differ. Similar specifications do not make these movements interchangeable.
Which functions will you use?
The 9039 keeps things to three hands. The 9015 adds a date, and the NH34A adds a GMT hand for another time zone. SW300-1 comes in date and no-date executions.
Watch the sweep.
3 Hz means six beats per second; 4 Hz means eight. The higher frequency gives finer steps, without promising better accuracy.
Look beyond the caliber.
Check the complete watch’s thickness, accuracy promise, warranty, and service options. The movement helps explain a watch; it does not tell the whole story.
New to movements?
A few words,
made clear.
A caliber is a movement’s model or design designation. The watch brand on the dial and the movement maker can be different companies.
See how an automatic works- Power reserve
- How long the watch can run from a full wind, without further winding.
- Hacking
- Stopping the seconds hand while you set the time.
- Regulation
- Adjusting the movement’s rate. A watch brand may specify a tighter tolerance than the movement maker.
- Jewels
- Bearings and other working surfaces inside the movement. A larger count is not a simple quality score.