Bezel Insert Dimensions for commonly modded Seiko Watches

Looking for the dimensions of a bezel insert? You've come to the right place!

We've compiled the bezel insert sizes of some of the most commonly modded Seiko dive watches. In this list, you'll find the bezel insert dimensions for the following watch models:

  • Seiko SKX007/SKX009/SKX173/SKX175
  • Seiko SKX013
  • Seiko SRP Turtle
  • Seiko SNZH
  • Seiko Sumo

For each bezel insert, we'll be sharing the Outer Diameter and Inner Diameter in millimetres (mm). Refer to the below images for an illustration of what the Outer Diameter and Inner Diameter are:

Outer Diameter

Bezel insert outer diameter

Inner Diameter

Bezel Insert Inner Diameter




Outer Diameter: 38.0 mm

Inner Diameter: 31.5 mm

Other case numbers that share the same bezel insert measurement: SKX173, SKX175, 6105-8110, 6306-7000, 6309-7040, 6309-7290, 7002, 7549.

Not sure how to check your case number? Check out this handy resource from Plus9Time for more information.



Outer Diameter: 33.7 mm

Inner Diameter: 27.5 mm


Seiko SRP Turtle

Outer Diameter: 39.1 mm

Inner Diameter: 32.5 mm


Seiko SNZH series

Outer Diameter: 39.5 mm

Inner Diameter: 32.5 mm


Seiko Sumo

Outer Diameter: 39.75 mm

Inner Diameter: 31.55 mm


We hope this list will be useful. Some of you message us asking if your Orient, Invicta or Glycine watches will be compatible with our aftermarket bezel inserts. By measuring the bezel insert of your watch and referring to this list, you'll be able to find your answer!

If you'd like to add to this list of bezel insert dimensions, do drop us a message at and we'll be happy to add it to this page.