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Flexi Shield 1
Flexi Shield 2
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Spira’s Flexi-Shield gasket offers the best of both worlds. This gasket combines the EMI shielding performance of our other spiral gaskets with the rain/wind/dust sealing of an elastomer. Just like all our gaskets, it builds on the architecture of our highly-conductive spiral. A special process wraps our highly conductive spiral around a soft silicone tube. The spiral is bonded to the inner tube so the ends will not unwrap when cut. This results in gaskets that are as easy to handle and use as a rubber elastomer and are rugged enough to be used in demanding sliding applications. The low force version provides as little as two pounds of closure force per inch, and different versions offer moderate to high shielding, depending on the materials chosen. The gasket is groove mounted and flexes easily to conform to the many shapes of today’s electronics. The low force series is especially well-suited to shielding the front/rear panels of VME/VXI and similar enclosures. Its low coefficient of friction makes it ideal for sliding applications and testing shows no visible wear after 1,000 insertions on a VME front panel.

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Flexi-Shield Part Numbers (Stainless Steel)Recommended Groove Dimensions*
DiameterStandard ForceModerate ForceLow ForceDepth (L) +.002”-.000”Width (G) +.007”-.005”Width (W) +.000”-.002”
.063”± .003”SQ-04MQ-04LQ-04.046”.094”.060”
.070”± .003”SQ-.070MQ-.070LQ-.070.053”.094”.067”
.094”± .004”SQ-06MQ-06LQ-06.070”.125”.090”
.103”± .004”SQ-.103MQ-.103LQ-.103.077”.141”.099”
.106”± .004”SQ-.106MQ-.106LQ-.106.080”.141”.102”
.125”± .004”SQ-08MQ-08LQ-08.094”.171”.121”
.139”± .005”SQ-.139MQ-.139LQ-.139.104".187".134"
.141”± .005”SQ-09MQ-09LQ-09.105”.187”.136”
.187”± .008”SQ-12MQ-12LQ-12.140”.250”.181”
.250”± .010”SQ-16MQ-16LQ-16.185”.343”.240”

* Different groove required for VME/VXI and similar front/rear panel shielding. Refer to our VME/VXI Shielding Design Guide for details.
Note: Larger sizes may be available. Contact us for more information.

Whether you need moderate to high shielding levels, rain/wind/dust sealing, or simply want the ease of handling that the inner tube provides, Spira’s Flexi-Shield comes through for you. All the benefits for one low cost!

Shielding Quality

We offer stainless steel for moderate shielding quality, and optional tin plating for higher shielding levels. All shielding quality results are based on tests against tin plated joint surfaces. The shielding quality may vary depending on your specific application.

Stainless Steel (All Forces): 100 dB at 1 GHz
Low Force Tin Plated Gaskets: 120 dB at 1 GHz
Moderate and Standard Force Tin Plated Gaskets: 130 dB at 1 GHz

Low Closure Force

The low force series is ideal for applications with very little closure force (approximately two pounds per linear inch compression). The gasket resists compression set, is very easy to handle and will provide a rain/wind/dust seal.

VME/VXI and Similar Front/Rear Panels

The low force gasket is the best choice for shielding front and back panels of VME/VXI and similar enclosures. The gaskets are easy to insert and testing shows no visible wear after 1,000 insertions! Flexi-Shield gaskets are manufactured from a continuous piece of metal, so they have no small pieces to break off and short out equipment. For specific design information, refer to our VME/VXI Shielding Design Guide.

Sliding Applications

All versions of Flexi-Shield are ideally suited for sliding applications. Specify moderate or standard force Flexi-Shield where extreme durability is required.


Spiral: Stainless steel (tin plating optional).
Inner Tubing: 60 durometer silicone.

Environmental Sealing

Our testing shows that all sizes and all resiliencies offer a rain/wind/dust seal. (We have other gaskets that provide an immersion seal). Contact us for free samples to determine if this gasket meets your environmental sealing needs!

Compression Force

Flexi-Shield gaskets come in three different resiliencies (as shown below). Optimal compression of the gasket is 25% of the diameter of the spiral (except in the case of VME/VXI designs. Please refer to our VME/VXI Shielding Design Guide). Since the force to compress the gasket is a function of the cube of the thickness of the stainless steel ribbon, the compression forces shown are approximate.

Standard Force: ~30 pounds per linear inch compression.
Moderate Force: ~10 pounds per linear inch compression.
Low Force: ~2 pounds per linear inch compression.


This gasket is groove mounted. Refer to our VME/VXI Shielding Design Guide for more information.

Materials and Plating

Plating for stainless steel Flexi-Shield can be specified using the following prefix:
T: Tin/lead plating over the stainless steel for better shielding quality Electroplated 90% tin, 10% lead (Example: TSQ-04)
IW: RoHS compliant tin plating (Example: IWSQ-04)

Tin plated beryllium copper material may be substituted if desired. An edge plated version is also available for high humidity/salt-fog environments. Please contact us for more information.

Special Tubing

Fluorosilicone tubing can be specified as follows (may include extra charges):
-F: Fluorosilicone tubing (Example: SQ-04-F)

Splicing Options

Spira has created three standard options to treat the splicing of material in our spool selection.

Ordering Information

Flexi-Shield is sold by the foot and typically packaged on spools except in small quantities. It can also be ordered cut-to-length in specific sizes or you can cut it yourself using a sharp pair of scissors. Not all configurations are stock items. Contact us for availability. Custom o-rings also available.

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