Free Shipping Across the USA — Worldwide Delivery Available!
PALM Parts Solution
AccountQuote
In Stock Fast Shipping Available
Keyence FU-21X flexible fiber optic sensor head for industrial automation

*Image shown is a representation only. Actual product may vary.

Keyence FU-21X

by Keyence

Read verified buyer reviews ↓

OverviewThe Keyence FU-21X is an advanced fiber optic sensor designed for outstanding adaptability and accuracy in demanding industrial settings. Crafted for flawless integration with Keyence FS Series fiber optic amplifiers, this sensor excels in scenarios requiring ultra-compact sensing and dynamic operation. Its defining characteristic is an exceptionally flexible fiber jacket, combined with a distinctive side-view sensing orientation, making it the perfect solution for identifying objects in confined spaces, on moving machinery, or within intricate robotics where conventional sensors struggle. The FU-21X prioritizes not only flexibility but also resilience. With superior resistance to repeated bending, vibration, and general environmental stresses, it guarantees sustained, precise detection, ensuring operational stability and reducing maintenance even in the most rigorous industrial conditions.Key Features Side-View Detection Incorporates an innovative 90° sensing angle, enabling accurate detection in applications that demand side access or where direct frontal sensing is unfeasible. Ultra-Flexible Jacket Constructed from a specialized, high-flex polymer, this sensor is engineered to withstand constant movement and navigate tight cable runs without performance degradation. Slim and Compact Design Its remarkably slender profile ensures a perfect fit for small-scale equipment, restricted mounting areas, or any application where minimal space is critical. High Durability Built for resilience, the FU-21X offers outstanding resistance to vibration, abrasion, and numerous bending cycles, guaranteeing an extended operational lifespan and reliability. Plug-and-Play with FS Series Ensures effortless compatibility and integration across a broad spectrum of Keyence FS Series amplifiers, including the FS-V10, FS-V20, and FS-N Series, streamlining setup and expandability. Technical Specifications Model: FU-21X Detection Type: Side-view reflective Fiber Length: 2 meters (customizable by trimming for optimal length in specific applications) Minimum Detectable Object: Approximately 0.005 mm (achievable when paired with a compatible FS amplifier, allowing for detection of incredibly small targets). Bend Radius: R4 mm or greater (demonstrates exceptional flexibility due to its high-flex sheath, facilitating tight installations). Temperature Range: –40 to +70°C (ensures dependable performance across a wide array of industrial temperatures). Jacket Type: High-flex, featuring a robust protective outer coating for enhanced durability and longevity. Mounting: Versatile mounting choices include screw mounting or employing an optional fiber clamp for secure installation. Compatible Amplifiers: Fully compatible with Keyence FS-V10/20 Series, FS-N Series, and other related fiber optic amplifier models. Applications Electronics and PCB Assembly Perfect for precise identification of tiny components and ensuring accurate alignment in the constricted spaces of electronics manufacturing. Automation Systems Engineered to withstand the continuous motion and vibration inherent in automated production lines, ensuring consistent and reliable sensing. Packaging Equipment Its slender design allows for seamless integration into narrow zones and complex machinery found in high-speed packaging operations. Precision Part Detection Delivers accurate, repeatable detection of even the smallest items, crucial for quality control and assembly processes in diverse industries. Why Choose?The Keyence FU-21X stands out as the top selection for demanding sensing applications due to its unique blend of flexibility, precision, and resilience. When confronted with tight installation limitations, dynamic settings, or the requirement to detect micro-targets, this sensor delivers unparalleled performance. Its robust construction ensures long-term stability and minimal downtime, while its intuitive design facilitates rapid integration.Order NowUpgrade your industrial automation processes with the Keyence FU-21X. Contact Palm Parts Solutions today to learn more or to place your order.FAQWhat makes the Keyence FU-21X suitable for tight spaces?The FU-21X features an ultra-flexible jacket, slim profile, and a unique side-view detection angle, allowing for easy installation and precise sensing in extremely confined or intricate environments.Which Keyence amplifiers are compatible with the FU-21X?This sensor is fully compatible with Keyence FS-V10/20 Series, FS-N Series, and other related fiber optic amplifier models, ensuring broad integration possibilities.Can the fiber length be adjusted?Yes, the 2-meter fiber can be user-cut to achieve the optimal length required for your specific application, providing enhanced customization.What is the smallest object the FU-21X can detect?When paired with a compatible FS amplifier, it can detect objects as small as approximately 0.005 mm, making it ideal for precision applications.How durable is the FU-21X in harsh industrial environments?The FU-21X is engineered for high durability, offering superior resistance to vibration, abrasion, and repeated bending, ensuring reliable performance and extended operational life in challenging conditions.

🇺🇸 Ships from our Florida warehouse
1-Year PALM Parts Warranty
CONDITION
$125.00
21 in stock

USA — Free FedEx Priority & UPS Ground · Worldwide shipping available

For more quantity please contact Customer Service

Experts Available 24/7 · 365
+1 (689) 263-1985
sales@palmpartssolution.com

Fast Shipping

Dispatched quickly on in-stock items via UPS, FedEx & DHL worldwide.

Availability

Thousands of parts in stock — ready for immediate dispatch from Florida.

Payment Flexibility

AMEX, Visa, MasterCard, PayPal, Discover and wire transfer accepted.

PRODUCT DETAILS

Keyence FU-21X

Overview

This is a genuine Keyence component from the Sensors family. PalmPartsSolution stocks it in new, refurbished, and surplus condition with tested warranty and same-day shipping on in-stock units.

Whether you are sourcing a like-for-like replacement for an existing installation, an emergency spare to keep a line running, or a qualified part for a new build, our team can confirm availability, revision, and lead time before you order.

Key Features

  • Genuine Keyence catalog part
  • Tested before shipment
  • Backed by PalmPartsSolution warranty
  • Cross-reference and revision assistance available
  • Compatible with the broader Keyence automation ecosystem
  • Engineered to integrate inside Sensors installations

Compatibility

When ordering, match the full catalog/part number, hardware revision, and firmware revision called out by your Keyence equipment. Where applicable, confirm:

  • Input/output voltage and current rating
  • Communication protocol and network role
  • Mounting form factor and footprint
  • Operating temperature, humidity, and IP rating
  • Required certifications (UL, CE, ATEX, marine, etc.)

Not sure which revision you need? Send us the catalog number on the nameplate and we will confirm the correct match.

Replacement Information

Three ways to source this part through PalmPartsSolution:

  1. Exact replacement — same Keyence catalog number, new or refurbished, tested and warrantied
  2. Form-fit-function equivalent — alternate revision or build that drops in without code changes
  3. Engineered migration — current-generation Keyence platform with documented conversion notes for the Sensors family

Contact our engineering team if you need help choosing between these tracks.

Technical Specifications

  • Model: FU-21X
  • Detection Type: Side-view reflective
  • Fiber Length: 2 meters (customizable by trimming for optimal length in specific applications)
  • Minimum Detectable Object: Approximately 0.005 mm (achievable when paired with a compatible FS amplifier, allowing for detection of incredibly small targets).
  • Bend Radius: R4 mm or greater (demonstrates exceptional flexibility due to its high-flex sheath, facilitating tight installations).
  • Temperature Range: –40 to +70°C (ensures dependable performance across a wide array of industrial temperatures).
  • Jacket Type: High-flex, featuring a robust protective outer coating for enhanced durability and longevity.
  • Mounting: Versatile mounting choices include screw mounting or employing an optional fiber clamp for secure installation.
  • Compatible Amplifiers: Fully compatible with Keyence FS-V10/20 Series, FS-N Series, and other related fiber optic amplifier models.

Applications

  • Electronics and PCB Assembly

    Perfect for precise identification of tiny components and ensuring accurate alignment in the constricted spaces of electronics manufacturing.

  • Automation Systems

    Engineered to withstand the continuous motion and vibration inherent in automated production lines, ensuring consistent and reliable sensing.

  • Packaging Equipment

    Its slender design allows for seamless integration into narrow zones and complex machinery found in high-speed packaging operations.

  • Precision Part Detection

    Delivers accurate, repeatable detection of even the smallest items, crucial for quality control and assembly processes in diverse industries.

Why Choose the FU-21X?

The Keyence FU-21X stands out as the top selection for demanding sensing applications due to its unique blend of flexibility, precision, and resilience. When confronted with tight installation limitations, dynamic settings, or the requirement to detect micro-targets, this sensor delivers unparalleled performance. Its robust construction ensures long-term stability and minimal downtime, while its intuitive design facilitates rapid integration.

Availability & Shipping

  • In stock: FU-21X ready for immediate dispatch from our Florida warehouse.
  • Free USA shipping: FedEx Priority (2–5 business days) and UPS Ground (3–5 business days). Expedited options available at checkout.
  • Worldwide delivery: FedEx International Priority (1–5 days), UPS International Priority (3–5 days), and USPS International (5–10 days) — rates calculated at checkout.
  • Bulk pricing: Volume discounts on request — contact our sales team for quantity quotes.
  • Buy with confidence: Every FU-21X ships with a 1-Year PALM Parts warranty and a 30-day return window.
SUPPORT

Frequently Asked Questions — Keyence

The FU-21X features an ultra-flexible jacket, slim profile, and a unique side-view detection angle, allowing for easy installation and precise sensing in extremely confined or intricate environments.

Machine down? We ship parts the same day.

New, surplus, and refurbished Keyence inventory in stock. Request a quote or speak directly with an automation specialist for emergency sourcing.

CUSTOMER REVIEWS

What Verified Buyers Say

No reviews yet for this product. Be the first verified buyer to share your experience — we email a review invitation after every purchase.

Independent Supplier Notice

PALM Parts Solution operates as an independent industrial automation supplier and is not an authorized distributor or affiliate of any listed manufacturer or brand name. Manufacturer trademarks and product names are used solely for identification purposes. Original manufacturer warranties do not apply. All products sold by PALM Parts are backed by our own 1-year warranty.

Product Condition & Firmware

All products are sold as new unless stated otherwise. Original manufacturer packaging may show signs of handling, storage, or shelf wear. Date codes and series may vary from current factory production. PALM Parts does not guarantee the presence, version, or compatibility of any firmware on PLC or automation products.

Are you an Electrical Distributor?Learn more about our distributor program

PALM Parts Solution sells used surplus products. PALM Parts Solution is not an authorized distributor, affiliate, or representative for the brands we carry. Products sold by PALM Parts Solution come with PALM Parts Solution's 1-Year Warranty and do not come with the original manufacturer's warranty. Designated trademarks, brand names and brands appearing herein are the property of their respective owners. This website is not sanctioned or approved by any manufacturer or tradename listed.

Read full disclaimer →