SEIKO 5 SRP721 Automatic Watch
Overview
The Seiko SRP721 is a 44mm men's automatic watch with a stainless steel case and a black-gray analog dial protected by hardlex crystal. It uses a 4R36 caliber self-winding mechanical movement that can be manually wound and hacked (the second hand stops 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 41 hours when fully wound and will self-wind when moved.
The SRP721 is currently ranked #450 in popularity out of 2,613 watches in this catalog. Check availability on Amazon.com. You can see other models similar to this one 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.
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SRP721 is only a partial model number. [learn more]
The case of the SRP721 measures approximately 44mm 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 watch has a display back to show of the 4R36 movement.The stainless steel bezel shows minute numbering and is fixed (cannot be rotated). The gap between the lugs is 22mm and the leather band can be removed using a band removal tool to be replaced with another band.
The SRP721 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.
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
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Search: eBay | Chrono24 - Popularity
#450 of 2,613 - Style Sports
- Gender Men's
Movement
- Type Automatic
- Caliber 4R36
- Jewels 24
- Beats per Hour 21,600 bph(6 bps)
- Power Reserve 41 Hours
- Manual Winding Yes
- Hacking Yes
- Instructions Owner's Manual
Case
- Case Width
44mm(without crown) - Case Thickness 12mm
- Case Shape Round
- Case Material Stainless Steel
- Case Code
- 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 22mm
- Replaceable Band Yes
- Band Material Leather
- Band Color Black
Dial
- Dial Color Black, Gray
- Dial Reference
- Hour Markings Circles, Triangles
- On the Dial
5 Shield, "Automatic", "SPORTS", Water Resistance
Bezel
- Bezel Color Black
- Bezel Function Fixed
- Bezel Material Stainless Steel
- On the Bezel Minute Numbering
Inner Bezel / Chapter Ring / Outer Dial
- Inner Bezel Color Black, Gray
- On Inner Bezel Bars
Hand Colors
- Hour Hand Silver
- Minute Hand Silver
- Second Hand Red 5, Silver
If you see anything that seems incorrect please let us know.
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