SEIKO Diver SNZB21 Automatic Watch
Overview
The Seiko SNZB21 (7S36-00Y0) is a 39mm men's automatic watch with a stainless steel case and a blue analog dial protected by hardlex crystal. It uses a 7S36 caliber self-winding mechanical movement that cannot be manually wound or hacked (the second hand does not stop when the crown is pulled out). It ticks 6 times per second which gives the second hand a smoother movement than quartz watches which tick once per second. The watch should run for up to 43 hours when fully wound and will self-wind when moved.
The SNZB21 is currently ranked #258 in popularity out of 751 watches in this catalog. Check availability on Amazon.com. This watch is part of a family of six watches that are identical except for their color or strap. You can see the other variations in this family as well as other similar models on the left side of the page. By clicking the checkbox under a similar model you can compare that model with this one side-by-side. We use nearly 100 different weighted criteria to calculate which models are the most similar to one another.
SNZB21 is only a partial model number. [learn more]
The case of the SNZB21 measures approximately 39mm wide (not including the crown) by 12mm thick and is water resistant to 100 meters. This should be sufficient for splashes, rain, baths, showers & swimming (shallow diving) but is not recommended for scuba diving. The crown does not screw down which increases the risk that it could be pulled out accidentally while under water. The stainless steel bezel shows minute numbering and can be rotated. The gap between the lugs is 20mm and the bracelet band can be adjusted to fit using a link removal tool or removed using a band removal tool to be replaced with another band.
The SNZB21 provides the following features and complications:
- Second hand
- Minute hand
- Hour hand
- Day window to show the day of the week including two language choices for the day (English and either Spanish, Arabic, Kanji, Chinese, French, German, Danish or Roman Numerals). When setting the day keep turning the crown to get to the next language. On most models SUN will be red and on some models SAT will be blue.
- Date window to show the day of the month. Note that some watches may be damaged if you attempt to change the date between 8:00 PM and 2:00 AM, in which case you should change the time to be outside that range first then reset the time after adjusting the date. Check your watch manual for details.
- Rotatable bezel
Seiko Date Finder
If you have this watch and want to know when it was made simply enter the six digit serial number from the caseback below then click Find Date. Learn more
Specifications [edit]
Full specifications are listed below. Please report any errors by clicking the edit link above then use the appropriate 
icon to provide your input.
General
- Retailers Check availability
Search: eBay | Chrono24 - Popularity
#258 of 751 - Style Sports, Diver
- Gender Men's
Movement
- Type Automatic
- Caliber 7S36
- Jewels 23
- Beats per Hour 21,600 bph(6 bps)
- Power Reserve 43 Hours
- Manual Winding No
- Hacking No
- Instructions Owner's Manual
Case
- Case Width
39mm(without crown) - Case Thickness 12mm
- Case Shape Round
- Case Material Stainless Steel
- Case Code 00Y0
- Crystal Material Hardlex
- Water Resistance 100 Meters(baths & shallow diving)
- Crown Position 03:00
- Screw Down Crown No
- Second Crown No
Complications
- Second Hand Yes
- Minute Hand Yes
- Hour Hand Yes
- Day Window Yes
- Date Window Yes
Band
- Band Width 20mm
- Replaceable Band Yes
- Band Material Bracelet
- Band Color Silver
Dial
- Dial Color Blue
- Dial Reference 01F4
- Hour Markings Bars
- On the Dial
5 Shield, "Automatic", "Jewels", "SPORTS", Water Resistance
Bezel
- Bezel Color Silver
- Bezel Function Unidirectional
- Bezel Material Stainless Steel
- On the Bezel Minute Numbering
Inner Bezel / Chapter Ring / Outer Dial
- Inner Bezel Color Blue
- On Inner Bezel Bars, Triangles
Hand Colors
- Hour Hand Silver
- Minute Hand Silver
- Second Hand Green
If you see anything that seems incorrect please let us know.
Back