Seiko Caliber NH25A VS. NH35A
What is the difference between Seiko caliber NH25 and NH35?
There are some differences between these overall similar movements. The differences are mostly convenience that give value to the collector. Please compare in the chart below. Did we miss anything? Please comment below.
|Seiko Caliber NH25A||Seiko Caliber NH35A|
|Year Introduced||(Please add to comments below)||2011?|
|Diameter||12”’ (27.40mm)||12”’ (27.40mm)|
|Power Reserve||> 41 Hours||> 41 Hours|
|Beats Per Hour||21,600 vph (6 vibrations per second)||21,600 vph (6 vibrations per second)|
|Hand-Winding?||NO!||Yes, can also be manual-wind|
|Crown||See chart below||See chart below|
|Quick Set Date?
|Models||Add yours to the comments below||Add yours to the comments below|
Time Module claims that the caliber NH25A is rated for a static accuracy of -25 ~ +35 seconds per day. The caliber NH35A clocks in at a static accuracy of -20 ~ +40 seconds per day under normal temperature conditions and without the calendar function. These measurements were taken within 10-60 minutes of being fully wound.
Difference Between Crown Functions
As we see here, the main differences between the two calibers is that the NH35A is hackable and can be hand-wound. That means the crown operates differently:
|Crown in position 0||Free (does nothing)||
|Crown in position 1||
|Crown in position 2||Time setting (second hand keeps going aka “doesn’t hack”)||Time setting (second hand stops aka “hacks”)|
Does my watch have the NH25A or NH35A movement?
It should say on the rotor. If it has a closed caseback or a custom rotor without any caliber markings, the easiest way to tell is to simply wind the crown (unscrew it first if your watch is a dive watch), is it winding the mechanism? Then it’s an NH35A. Pull the crown out two clicks (to position 2 aka time setting mode), does it stop the second hand? Then it’s the NH35A.
Which one is the better movement?
That is up for debate! We’d love to hear your thoughts in the thread below. Why do you like one over the other? What are the advantages of one over the other?
NH25A VS NH35A Drawings
- Caliber NH35A full thread with examples and specs
- NH25 Thread coming soon but we need high quality pics!
Also keep in mind that although the NH25 and NH35 calibers are the most talked about, there is actually a slew of other NH calibers: NH05, NH15, NH06, NH16, NH36, NH37, NH38, NH39, NH70, etc