JIS B2401 EMI O-Rings
SSP fabricates JIS B2401 EMI O-Rings from the electrically conductive silicones that we make. These conductive O-rings provide environmental sealing and EMI shielding and are fabricated at our Made in USA manufacturing facility.
- Base elastomers: Silicone or fluorosilicone
- Conductive particles: Silver-aluminum, silver-copper, silver-nickel, nickel-aluminum, or nickel-graphite
- Manufacturing: Molded or bonded
JIS B2401 EMI O-Ring Series
JIS B2401 dimensions are divided into series based on application:
P Series: Moving / Dynamic Sealing
G Series: Fixed / Static Sealing
S Series: Small / Slim Hardware
Popular JIS B2401 EMI O-Ring Sizes
The table below provides common JIS B2401 dimensional specifications used when ordering metric EMI O-rings.
JIS Part Number | Series Type | Cross Section (CS) | Inner Diameter (ID) | Nominal CS (Inches) | Nominal ID (Inches) |
P3 | P (Dynamic) | 1.90 mm | 2.80 mm | 0.075 in | 0.110 in |
P4 | P (Dynamic) | 1.90 mm | 3.80 mm | 0.075 in | 0.150 in |
P5 | P (Dynamic) | 1.90 mm | 4.80 mm | 0.075 in | 0.189 in |
P6 | P (Dynamic) | 1.90 mm | 5.80 mm | 0.075 in | 0.228 in |
P7 | P (Dynamic) | 1.90 mm | 6.80 mm | 0.075 in | 0.268 in |
P8 | P (Dynamic) | 1.90 mm | 7.80 mm | 0.075 in | 0.307 in |
P9 | P (Dynamic) | 1.90 mm | 8.80 mm | 0.075 in | 0.346 in |
P10 | P (Dynamic) | 1.90 mm | 9.80 mm | 0.075 in | 0.386 in |
G25 | G (Static) | 3.10 mm | 24.40 mm | 0.122 in | 0.961 in |
G30 | G (Static) | 3.10 mm | 29.40 mm | 0.122 in | 1.157 in |
G35 | G (Static) | 3.10 mm | 34.40 mm | 0.122 in | 1.354 in |
G40 | G (Static) | 3.10 mm | 39.40 mm | 0.122 in | 1.551 in |
G50 | G (Static) | 3.10 mm | 49.40 mm | 0.122 in | 1.945 in |
S3 | S (Slim) | 1.50 mm | 2.50 mm | 0.059 in | 0.098 in |
S5 | S (Slim) | 1.50 mm | 4.50 mm | 0.059 in | 0.177 in |
S10 | S (Slim) | 1.50 mm | 9.50 mm | 0.059 in | 0.374 in |
S15 | S (Slim) | 1.50 mm | 14.50 mm | 0.059 in | 0.571 in |
S20 | S (Slim) | 1.50 mm | 19.50 mm | 0.059 in | 0.768 in |
JIS B2401 EMI O-Ring Applications
Primary applications and industries include:
Aerospace & Avionics
Flight Control & Navigation Systems: Shielding sensitive control units and radar/communication electronics from high-frequency electromagnetic interference (EMI) and radio frequency interference (RFI).
Satellite Communications (SATCOM): Preventing signal crosstalk and protecting sensitive transceiver hardware exposed to extreme thermal cycling.
Defense & Military Electronics
Ruggedized Tactical Radios & Gear: Providing high decibel (dB) shielding effectiveness to meet strict military standards (such as MIL-DTL-83528 and MIL-STD-461) while keeping field equipment IP-rated against water and dust ingress.
Missile Guidance Systems & Radar Enclosures: Protecting internal guidance electronics from intense external pulse interference and severe vibration.
Medical Devices & Equipment
Diagnostic & Imaging Systems: Shielding sensitive electronics in MRI components, ultrasound machines, and precision laboratory monitors where small amounts of stray radiation or external noise can ruin diagnostic readings.
Portable Life-Support Systems: Preventing external wireless or cellular signals from interfering with digital control units.
Automotive & Electric Vehicles (EV)
Inverters & Power Electronics: Shielding high-voltage EV battery management systems (BMS), motor controllers, and onboard chargers to prevent severe high-frequency switching noise from disrupting lower-voltage vehicle networks (CAN/LIN buses).
ADAS (Advanced Driver Assistance Systems): Sealing radar, LIDAR, and camera control modules against environmental moisture while maintaining noise isolation.
Telecommunications & Industrial Infrastructure
5G Outdoor Base Stations & Enclosures: Protecting sensitive high-frequency RF modules from weather elements (rain, humidity, dust) while maintaining high shielding performance.
Industrial Automation & Robotics: Protecting programmable logic controllers (PLCs) and sensor junction boxes in harsh industrial environments with heavy electrical noise from motors and drives.