Festo ESNU Single-Acting Round Cylinder — ISO 6432 Spring Return Pneumatic Actuator (46 Models) Specs & Selection Guide
2026-06-14
The Festo ESNU Series Single-Acting Round Cylinder is an economical pneumatic actuator conforming to ISO 6432 standards, specifically designed for applications requiring pneumatic drive in one direction with spring return. The ESNU series offers an extensive range of derivatives across 10 piston diameters from 8mm to 63mm, with optional internal or external piston rod threads to meet diverse application requirements. With its excellent operating performance, long service life, and quick and easy installation, the ESNU is the ideal choice for reliable linear motion in compact spaces.
Key Features & Highlights
- Single-Acting Design: Only one air supply port required — compressed air drives one direction, spring returns the opposite direction, simplifying pneumatic circuit design and control
- ISO 6432 Standard: Internationally standardized mounting interfaces for easy replacement and system integration
- Extensive Derivative Range: 10 piston diameters (8–63mm) plus multiple stroke options for customized applications
- Internal/External Piston Rod Thread: Flexible adaptation to different connection and mounting requirements
- High Operating Performance: Optimized pneumatic design ensures efficient energy conversion
- Long Service Life: High-quality seals and precision manufacturing for long-term reliable operation
- Quick and Easy Installation: Compact round design enables fast mounting even in tight spaces
Technical Specifications
| Parameter | Specification |
|---|---|
| Series | ESNU |
| Type | Single-Acting Round Cylinder (Spring Return) |
| Piston Diameter Range | 8 / 10 / 12 / 16 / 20 / 25 / 32 / 40 / 50 / 63 mm |
| Stroke Range | 10 / 25 / 50 mm |
| Cushioning | P – Adjustable pneumatic cushioning (optional) |
| Operating Mode | Single-acting: Compressed air advances, spring force returns |
| Piston Rod Thread | Internal or external thread available |
| Standard | ISO 6432 |
| Operating Medium | Compressed air, lubricated or non-lubricated |
| Position Sensing | Supported via proximity sensors |
Model Number Naming Convention
The ESNU series model naming format is: ESNU-[Piston Diameter]-[Stroke]-P-A
- ESNU: Series designation — Single-Acting Round Cylinder (ISO 6432)
- Piston Diameter: 8 / 10 / 12 / 16 / 20 / 25 / 32 / 40 / 50 / 63 mm
- Stroke: 10 / 25 / 50 mm (empty for base models)
- P: Adjustable pneumatic cushioning (may not be present on base models)
- A: Standard connection type
Complete ESNU Series Model List
The following table lists all 46 standard models in the FESTO ESNU series:
| Order Code | Part Number | Piston Diameter (mm) | Stroke (mm) | Type |
|---|---|---|---|---|
| ESNU-8- -P-A | 14119 | 8 | – | Standard (-mm Stroke) |
| ESNU-8- – | 193996 | 8 | – | Base (No Cushioning) |
| ESNU-8-10-P-A | 19254 | 8 | 10 | Standard (10mm Stroke) |
| ESNU-8-25-P-A | 19255 | 8 | 25 | Standard (25mm Stroke) |
| ESNU-8-50-P-A | 19256 | 8 | 50 | Standard (50mm Stroke) |
| ESNU-10- -P-A | 14118 | 10 | – | Standard (-mm Stroke) |
| ESNU-10- – | 193997 | 10 | – | Base (No Cushioning) |
| ESNU-10-10-P-A | 19257 | 10 | 10 | Standard (10mm Stroke) |
| ESNU-10-25-P-A | 19258 | 10 | 25 | Standard (25mm Stroke) |
| ESNU-10-50-P-A | 19259 | 10 | 50 | Standard (50mm Stroke) |
| ESNU-12- -P-A | 14317 | 12 | – | Standard (-mm Stroke) |
| ESNU-12- – | 193998 | 12 | – | Base (No Cushioning) |
| ESNU-12-10-P-A | 19260 | 12 | 10 | Standard (10mm Stroke) |
| ESNU-12-25-P-A | 19261 | 12 | 25 | Standard (25mm Stroke) |
| ESNU-12-50-P-A | 19262 | 12 | 50 | Standard (50mm Stroke) |
| ESNU-16- -P-A | 14316 | 16 | – | Standard (-mm Stroke) |
| ESNU-16- – | 193999 | 16 | – | Base (No Cushioning) |
| ESNU-16-10-P-A | 19263 | 16 | 10 | Standard (10mm Stroke) |
| ESNU-16-25-P-A | 19264 | 16 | 25 | Standard (25mm Stroke) |
| ESNU-16-50-P-A | 19265 | 16 | 50 | Standard (50mm Stroke) |
| ESNU-20- -P-A | 14319 | 20 | – | Standard (-mm Stroke) |
| ESNU-20- – | 194000 | 20 | – | Base (No Cushioning) |
| ESNU-20-10-P-A | 19266 | 20 | 10 | Standard (10mm Stroke) |
| ESNU-20-25-P-A | 19267 | 20 | 25 | Standard (25mm Stroke) |
| ESNU-20-50-P-A | 19268 | 20 | 50 | Standard (50mm Stroke) |
| ESNU-25- -P-A | 14318 | 25 | – | Standard (-mm Stroke) |
| ESNU-25- – | 194001 | 25 | – | Base (No Cushioning) |
| ESNU-25-10-P-A | 19269 | 25 | 10 | Standard (10mm Stroke) |
| ESNU-25-25-P-A | 19270 | 25 | 25 | Standard (25mm Stroke) |
| ESNU-25-50-P-A | 19271 | 25 | 50 | Standard (50mm Stroke) |
| ESNU-32- – | 194002 | 32 | – | Base (No Cushioning) |
| ESNU-32-10-P-A | 196376 | 32 | 10 | Standard (10mm Stroke) |
| ESNU-32-25-P-A | 196377 | 32 | 25 | Standard (25mm Stroke) |
| ESNU-32-50-P-A | 196378 | 32 | 50 | Standard (50mm Stroke) |
| ESNU-40- – | 194003 | 40 | – | Base (No Cushioning) |
| ESNU-40-10-P-A | 196379 | 40 | 10 | Standard (10mm Stroke) |
| ESNU-40-25-P-A | 196380 | 40 | 25 | Standard (25mm Stroke) |
| ESNU-40-50-P-A | 196381 | 40 | 50 | Standard (50mm Stroke) |
| ESNU-50- – | 194004 | 50 | – | Base (No Cushioning) |
| ESNU-50-10-P-A | 196382 | 50 | 10 | Standard (10mm Stroke) |
| ESNU-50-25-P-A | 196383 | 50 | 25 | Standard (25mm Stroke) |
| ESNU-50-50-P-A | 196384 | 50 | 50 | Standard (50mm Stroke) |
| ESNU-63- – | 194005 | 63 | – | Base (No Cushioning) |
| ESNU-63-10-P-A | 196385 | 63 | 10 | Standard (10mm Stroke) |
| ESNU-63-25-P-A | 196386 | 63 | 25 | Standard (25mm Stroke) |
| ESNU-63-50-P-A | 196387 | 63 | 50 | Standard (50mm Stroke) |
Application Industries
- Automated Assembly Lines: Single-acting design simplifies pneumatic control for clamping, positioning, and ejecting operations
- Packaging Machinery: Spring return ensures safe retraction on air loss, suitable for sealing and pushing stations
- Electronics Manufacturing: Small bore models (8–16mm) ideal for precision component pick-and-place operations
- Medical Devices: Compact dimensions and reliable spring return for analytical instruments and laboratory equipment
- General Industrial Automation: Suitable for various fixtures, stops, and pusher mechanisms requiring simple linear motion
Related Series
- DSNU Series: Double-acting round cylinder, ISO 6432, for broader applications
- DSNU-S Series: Short round cylinder with self-locking mechanism
- CRHD Series: Stainless steel round cylinder for corrosive environments
Frequently Asked Questions
Q: What is the difference between ESNU single-acting and DSNU double-acting cylinders?
A: ESNU is a single-acting cylinder with only one supply port — compressed air drives the piston in one direction and a built-in spring returns it. DSNU is a double-acting cylinder with two supply ports — compressed air alternately drives the piston in both directions. ESNU advantages include simplified pneumatics (only one control valve needed), automatic spring return on air loss (safety feature), and lower energy consumption (air consumed only during advance). DSNU offers higher output force and controllable bidirectional motion.
Q: How do I select the right ESNU spring return force?
A: The ESNU series features a built-in return spring with force values standardized by Festo based on piston diameter and stroke, ensuring reliable return performance. The spring is designed for reliable return under no-load or light-load conditions. If your application involves significant reverse loads or friction, verify spring return force adequacy or consider switching to the double-acting DSNU series. Refer to the FESTO official technical manual for specific spring force values.
Q: What mounting options are available for the ESNU series?
A: The ESNU series supports multiple mounting methods, including: direct mounting via mounting nut (body thread), flange mounting, foot mounting, and trunnion mounting. Base models (without stroke specification) are primarily intended as spare parts or configuration bases — standard models with specified strokes are typically used in actual applications. Refer to the FESTO accessories catalog for specific mounting hardware details.
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Disclaimer: Product images and some technical specifications on this page are sourced from the official Festo website. All trademarks are the property of their respective owners.