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June 24, 2020 2 min read

Last Update: 24 Mar 2021

24/03/2021: SEIKO have currently released various different case dimensions. Compatibility only applies to 5KX models with rotatable bezels. 5KX models with pilot bezel are excluded from this compatibility topic.


In the last quarter of 2019, SEIKO announced and released new models to replace the SKX series, namely SKX007, SKX009 and SKX011. These new models are the SRPD/SRPE series - successor to the now discontinued SKX series. They were released as Seiko 5 Sports line-ups , also known in short as the "5KX" within the watch community. Listed here are the 5KX models that has rotatable bezel with insert:

  • Sports Style: SRPD51K1, SRPD51K2, SRPD53K1, SRPD55K1, SRPD55K3, SRPD57K1, SRPD59K1, SRPD61K1, SRPD63K1, SRPD65K1, SRPD65K4
  • Suits Style: SRPE75K1, SRPE77K1, SRPD65K2, SRPD67K1, SRPD69K1, SRPD71K1, SRPD71K2, SRPD73K1, SRPD73K2, SRPD75K1
  • Specialist Style: SRPE79K1, SRPE80K1, SRPD55K2, SRPD65K3, SRPD76K1
  • Street Style: SRPE71K1, SRPE72K1, SRPE74K1, SRPD79K1, SRPD81K1, SRPD83K1
  • Sense Style: SRPE83K1, SRPD77K1, SRPD85K1


Naturally, what's on everyone's mind would be the major difference between SKX007 and SRPD/SRPE series. In short, these are the differences:

Caseback Solid Steel See-through (Crystal)
Crown Screw-down Push/pull
Movement 7S26 (Non-hacking) 4R36 (Hacking)
ISO 6425 Certified Yes No
Water Resistant Diver's 200m 100m


This of course sent shockwaves across the entire watch community having, particularly, Seiko mod enthusiasts apprehensive about the discontinued SKX series yet elated with novel releases.

Given that existing mod parts on the market were originally designed for SKX007, a concerning question rose among enthusiasts,

"Are the mod parts for SKX007 compatible with the new SRPD/SRPE series?"


Here is a quick table to identify what parts are interchangeable or compatible between the SKX007 and SRPD/SRPE series. 

Parts Interchangeable / Compatible
Bezel Insert
Chapter Ring
Gasket - Caseback
Gasket - Crystal
Spring Bars


With increasing models releases by SEIKO, please note that all listed compatibility refers only to 5KX models with rotatable bezel. 5KX models with pilot bezel are excluded from this compatibility topic.



The four parts that are incompatible: the crownspring bars, caseback gasket and crystal gasket. Given that SKX007 is screw-down crown, it make sense that it does not fit SRPD/SRPE push/pull crown. For spring bars, the SRPD/SRPE series have slightly smaller ends. Thus, SKX007 fat spring bars wouldn’t fit into SRPD/SRPE cases. However, because SRPD/SRPE spring bars have smaller ends, they do fit into SKX007 case.



Fortunately for the rest of the most frequently modded parts - the bezels, bezel inserts, chapter rings, crystals, dials and hands have exact fitting dimensions between SKX007 and SRPD/SRPE series; thus, allowing ease of interchangeable and are fully compatible. In other words, these compatible parts designed for SKX007 will fit perfectly well in SRPD/SRPE series.


With all these essential Seiko modding information in mind, you will be in a good position to know that whichever model you selected from SRPD/SRPE series as a Seiko mod base, you will be able to modify just about all the parts.


Want to learn more about watch modding? Check out our tutorial posts 

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