JIS B 2401 is a Japanese Industrial Standard for O-Ring sizes.
This standard, often referred to as “Japanese Metrics”, is organized into four series, based on their application.
The O-Rings in each section have ascending number codes to complete the size reference.
- JIS: P Series – Moving (dynamic)
- JIS: G Series – Fixed (static)
- JIS: S Series – Special Sizes
- JIS: V Series – Vacuum Flange
- All JIS Sizes – Sorted by Size

Material: Nitrile Rubber 90 Shore

G40 - ID 39.4mm x CS 3.1mm

Fix it right the first time, every time!
Engineered to surpass or meet OEM specifications.
Tested for durability, reliability, and performance.
Products are packaged professionally to prevent any type of damage during transit.
Want to confirm your part number or need any assistance?
We'll be happy to help!