DIN 3771 Silicone O-rings
Manufacturer & Custom Solutions
DIN 3771 Silicone O-rings
German DIN 3771 metric O-rings are a staple in European hydraulic and pneumatic systems. ZSR Silicone produces these seals with tight tolerances using VMQ, FVMQ and custom-blended silicone compounds. Whether you need standard sizes or custom dimensions, we can help.
FDA 21 CFR 177.2600
Rubber Articles Intended for Repeated Use
LFGB 30&31
EU Food Contact Materials
USP Class VI / ISO 10993
Biocompatibility of Medical Devices
RoHS / REACH
Environmental Compliance
UL 94
Flammability of Plastic Materials
Built to Your Exact Spec
Custom Silicone O-Rings Options
Every Silicone Grade, One Perfect Seal
Every O-ring starts with the right compound. Platinum-cured and peroxide-cured systems are available for all grades — we recommend platinum cure for food and medical contact.
| Grade | Hardness (Shore A) | Temperature | Compliance | Best For |
|---|---|---|---|---|
| Industrial VMQ | 30 – 80 | -60°C to +230°C | RoHS / REACH | General industrial sealing |
| FDA Food Grade | 30 – 70 | -60°C to +230°C | FDA 21 CFR 177.2600 | Food & beverage equipment |
| Medical Grade (Platinum) | 10 – 70 | -60°C to +230°C | USP Class VI | Medical devices & laboratory |
| High Temperature | 40 – 80 | up to +300°C | RoHS | Ovens, lighting, engine bays |
| Fluorosilicone (FVMQ) | 40 – 80 | -60°C to +200°C | RoHS | Fuel, oil & solvent exposure |
| LSR (Liquid Silicone) | 10 – 80 | -60°C to +230°C | FDA / medical grades | High-volume precision parts |
| Transparent / Clear | 30 – 70 | -60°C to +200°C | FDA options | Visual inspection points |
From 0.5 mm ID to Oversized Joint Rings
Size, cross-section and tolerance are fully custom. Send a drawing, a standard size number (e.g., AS568-214), or a physical sample — we handle the rest.
| Item | Range / Options |
|---|---|
| Size Range | ID 0.5 – 500 mm+; molded or vulcanized-joint for oversized IDs |
| Cross-Section | 0.5 – 10 mm; round (standard), square-cut, custom profile |
| Size Standards | AS568 · JIS B2401 · BS 1806 · DIN 3771 · ISO 3601 · ISO 6149 · AN6227 / AN6230 (see standards table below) |
| Tolerance | ISO 3302-1 class per size & process; ±0.05 mm on small molded rings |
| Custom Geometry | Non-standard ID / cross-section from your drawing or sample |
| Surface | Standard finish / PTFE-coated for low friction |
Any Color Your Brand or Assembly Needs
We color-match silicone compounds to Pantone or RAL references, including translucent and transparent grades for visual inspection points.
Your Brand, Built Into the Part
Branding, part numbers and batch traceability — molded in, engraved or printed, without compromising the seal.
Molded, Spliced or Coated — One Factory
Molding, splicing and finishing under one roof — we match the process to your volume, size and tolerance target.
| Process | How It Works | Best For |
|---|---|---|
| Compression Molding | Pre-formed silicone pressed and cured in a heated mold | Medium volumes, large cross-sections |
| LSR Injection Molding | Liquid silicone injected into closed molds | High volumes, tight tolerances |
| Vulcanized Joint (Spliced) | Extruded cord cut to length and vulcanized into a ring | Oversized IDs, low volumes, fast tooling |
| PTFE Coating | Low-friction coating applied to finished rings | Dynamic sealing, easy installation |
| Rapid Prototyping | Prototype tooling before production mold | Fit & function validation |
Related Silicone O-ring
| Image | Product | Type | Short Info | Action |
|---|---|---|---|---|
| BS 1806 Silicone O-rings | Standard & Size | British Standard inch-size silicone O-rings. Common in UK and Commonwealth industrial equipment. | View Details |
|
| DIN 3771 Silicone O-rings | Standard & Size | German metric standard O-rings for hydraulic and pneumatic sealing in European machinery. | View Details |
|
| Custom Molded Silicone O-rings | Standard & Size | Custom-shaped silicone O-rings molded to your exact drawing or sample. No standard size limitations. | View Details |
| AS568 Silicone O-rings | Standard & Size | Inch-size silicone O-rings that follow the AS568 standard. Widely used in North American machinery and hydraulic systems. | View Details |
| AN6227 Silicone O-rings | Standard & Size | Aerospace-standard O-rings with small cross-section. Used in aviation and military-grade sealing. | View Details |
| JIS B2401 Silicone O-Ring | Standard & Size | Japanese industrial standard O-rings commonly used in Asian-manufactured machinery and automotive equipment. | View Details |
| ISO 3601 Metric Silicone O-Rings | Standard & Size | Metric silicone O-rings manufactured to ISO 3601 dimensions. Fits international equipment groove standards. | View Details |
| ISO 6149 Metric Silicone O-Rings | Standard & Size | Metric O-rings designed for hydraulic and pneumatic fluid power sealing applications under ISO 6149 standards. | View Details |
| FDA Food Grade Silicone O-Rings | Grade | Food-safe silicone O-rings compliant with FDA regulations. Safe for repeated food contact. | View Details |
| Industrial Grade Silicone O-ring | Grade | General-purpose silicone O-rings for industrial sealing. Cost-effective with reliable performance. | View Details |
| Medical Grade Silicone O-ring | Grade | Biocompatible silicone O-rings for medical devices. Passes USP Class VI and supports sterilization. | View Details |
| High Temperature / Heat Resistant Silicone O-Rings | Special Function | Silicone O-rings that stay flexible at temperatures above 200°C. For ovens, engines and furnaces. | View Details |
| Oil-Resistant / Fuel-Resistant Silicone O-Rings | Special Function | Modified silicone O-rings that resist swelling in oils, fuels and petroleum-based fluids. | View Details |
 | VMQ Silicone O-Rings | Materials | Heat and cold-resistant silicone O-rings for food, medical, automotive, and industrial applications. | View Details |
| HCR / HTV / Solid Silicone Rubber O-rings | Materials | Durable solid silicone rubber O-rings made by compression molding. The standard choice for general sealing. | View Details |
| Fiberglass Reinforced Silicone O-rings | Materials | High-strength silicone O-rings reinforced with fiberglass fabric. Withstands extreme heat and pressure. | View Details |
| Liquid Silicone Rubber (LSR) O-rings | Materials | Injection-molded liquid silicone rubber O-rings with tight tolerances and clean surfaces. Ideal for high-volume production. | View Details |
| Platinum Cured Silicone O-rings | Materials | Ultra-clean silicone O-rings cured with platinum catalyst. Lower extractables for food and medical use. | View Details |
 | Fluorosilicone (FVMQ) O-rings | Materials | Fuel and oil-resistant silicone O-rings for aerospace, automotive and chemical applications. | View Details |
| Transparent / Clear Silicone O-rings | Color | See-through silicone O-rings for visual inspection and clean-looking medical or food equipment. | View Details |
| Custom Colors Silicone O-rings | Color | Silicone O-rings matched to your exact color sample or specification. | View Details |
What is DIN 3771 Standard?
DIN 3771 is a German standard for O-ring sizes, issued by the German Institute for Standards (Deutsches Institut für Normung). This standard identifies O-ring sizes by their inner diameter and cross-section (ID x C/S), and may include a letter indicating the quality level (N for normal quality, S for special quality) along with a code for the rubber material and hardness. DIN 3771 is widely used in German and European machinery, automotive, and industrial equipment where metric sizing is required.
ZSR Silicone manufactures silicone O-rings that fully match DIN 3771 standard sizes. If your equipment follows German or European design specifications and requires metric O-rings with defined quality grades, we can supply the correct DIN 3771 size in the silicone material that matches your application needs.
DIN 3771 vs. Other O-Ring Standards
Feature | DIN 3771 | AS568 / BS 1806 / AN Standards |
|---|---|---|
Origin | Germany (Deutsches Institut für Normung) | United States (SAE / MIL) |
Sizing system | Metric (millimeters) | Imperial (inch-based) |
Size identification | ID x C/S (inner diameter x cross-section) | |
Quality grades | N (normal) and S (special) quality levels | Not specified in the same way |
Material/hardness coding | Included in the size designation | Separate from size designation |
Regional use | Germany and Europe | Worldwide, especially Americas and Asia |
Simple DIN 3771 Silicone O-rings Size Chart
Important: About DIN 3771 Size Naming
DIN 3771 uses metric measurements (millimeters), and it identifies sizes by the actual inner diameter and cross-section dimensions (for example, 20 x 2 mm). Other standard like AS568 use dash numbers (like AS568-210) that do not directly show the dimensions.
DIN 3771 Standard No. Range | CS (mm) | ID Range (mm) | OD Range (mm) | CS (inch) | ID Range (inch) | OD Range (inch) |
|---|---|---|---|---|---|---|
1.8 X 1.8 ~ 17 X 1.8 | 1.80 | 1.80 ~ 17.00 | 5.40 ~ 20.60 | 0.071 | 0.071 ~ 0.669 | 0.213 ~ 0.811 |
14 X 2.65 ~ 38.7 X 2.65 | 2.65 | 14.00 ~ 38.70 | 19.30 ~ 44.00 | 0.104 | 0.551 ~ 1.524 | 0.760 ~ 1.732 |
18 X 3.55 ~ 200 X 3.55 | 3.55 | 18.00 ~ 200.00 | 25.10 ~ 207.10 | 0.140 | 0.709 ~ 7.874 | 0.988 ~ 8.154 |
40 X 5.3 ~ 400 X 5.3 | 5.30 | 40.00 ~ 400.00 | 50.60 ~ 410.60 | 0.209 | 1.575 ~ 15.748 | 1.992 ~ 16.165 |
206 X 7 ~ 670 X 7 | 7.00 | 206.00 ~ 670.00 | 220.00 ~ 684.00 | 0.276 | 8.110 ~ 26.378 | 8.661 ~ 26.929 |