Gardner Bender 3/8" Thread Met...
IN STOCK (leaves warehouse same day if ordered before 3pm ET)
$64.71
$16.41
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Gardner Bender 3/8" Thread Metal Knockout Seal with Self-Centering Design

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Model: KO709

In Stock (leaves warehouse same day if ordered before 3pm ET)

$64.71
$16.41
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Gardner Bender 3/8" Thread Metal Knockout Seal with Self-Centering Design

Professional knockout sealing solution for electrical enclosures

The Gardner Bender 3/8" Thread Metal Knockout Seal delivers reliable sealing performance for unused knockouts in electrical boxes and enclosures. Constructed from 16-gauge rust-proofed, cold-rolled galvanized steel with zinc-plated hardware, this professional-grade seal installs quickly from inside or outside of the box with embossed self-centering design for precise positioning.

Professional Features & Benefits

  • 16-Gauge Galvanized Steel Construction: Provides durable, corrosion-resistant sealing that maintains integrity in demanding electrical environments.
  • 3/8" Thread Specification: Ensures proper fit and secure installation in standard knockout openings for reliable long-term performance.
  • Self-Centering Embossed Design: Eliminates guesswork during installation with quick, accurate positioning in unused knockouts.
  • Single Screw Installation: Streamlines the sealing process with simple, secure mounting that holds the seal firmly in place.
  • Zinc-Plated Hardware: Screw and bar components resist corrosion and provide lasting durability in various environmental conditions.
  • Inside/Outside Installation Capability: Offers installation flexibility to accommodate different box configurations and access requirements.
  • Size and Catalog Marking: Clearly marked identification ensures proper selection and simplifies inventory management.

Technical Specifications

  • Each In Package Height In: 5.25
  • Each In Package Length Depth In: 1.25
  • Each In Package Weight Oz: 64.3
  • Each In Package Width In: 5.13

Professional Applications

  • Electrical Panel Sealing
  • Junction Box Maintenance
  • Commercial Electrical Installations
  • Industrial Enclosure Sealing
  • Residential Electrical Upgrades
  • Maintenance and Retrofit Projects
  • Code Compliance Applications

Why Choose Gardner Bender Quality?

Gardner Bender knockout seals combine professional-grade materials with practical design features for reliable electrical enclosure sealing. The rust-proofed galvanized steel construction and zinc-plated hardware ensure long-lasting performance, while the embossed self-centering design and clear marking system support efficient installation and maintenance practices.

Manufacturer Resources

Product Specs

Each In Package Height In :
5.25
Each In Package Length Depth In :
1.25
Each In Package Weight Oz :
64.3
Each In Package Width In :
5.13

Gardner Bender KO709 – Frequently Asked Questions

1) Can a knockout seal be installed from outside the panel if I can't get inside the box?
Yes. The Gardner Bender 3/8 inch metal knockout seal installs from either the inside or the outside of the box, which matters on a live panel or a mounted enclosure where you can't reach behind the wall. It goes in with a single screw, and the embossed self-centering face drops it into the hole without fussing over alignment.
2) Is a metal knockout seal better than a plastic knockout plug for a commercial panel?
The Gardner Bender KO709 is 16-gauge cold-rolled galvanized steel with a zinc-plated screw and bar, which is the type you want in a metal enclosure where the closure needs to match the box material and stand up to a shop or industrial environment. Snap-in plastic plugs are quicker and cheaper for dry residential work, but they are not steel and they do not clamp with a screw and bar the way this does.
3) Will a galvanized knockout seal hold up in a damp or corrosive environment?
The steel is rust-proofed, cold-rolled galvanized and the screw and bar hardware is zinc plated, so it resists corrosion in industrial and outdoor-adjacent enclosures. It is a sealing closure for an unused knockout, not a gasketed raintight fitting, so for a wet-location enclosure rating you should use a closure specified for that enclosure type.
4) Do I need any extra hardware to install the Gardner Bender KO709 knockout seal?
No extra parts. The seal comes with its own zinc-plated screw and bar, and that single screw is all that holds it. You need a screwdriver or nut driver and nothing else, which is why these are a common bulk stock item on maintenance carts.
5) Why do I have to fill an open knockout in a junction box at all?
An unused knockout leaves an open hole in the enclosure, which is why inspectors flag them on panel and junction box work. The Gardner Bender 3/8 inch metal seal closes that opening with a steel closure held by a screw and bar, and it is the standard fix on maintenance and retrofit jobs where conduit has been removed and the hole left behind.
6) How do I identify a knockout seal once it's in the bin with the others?
Each Gardner Bender seal is stamped with its size and catalog marking, so a 3/8 inch KO709 can be sorted out of a mixed drawer without gauging it. That marking is the reason these work well as a standardized stock item across a building's panels.
How fast can I get the Gardner Bender KO709 delivered?
Most orders ship the same day from our distribution partners, with quick delivery throughout the continental U.S. Need it urgently? Contact Us for expedited shipping options.
Can I return it if it doesn’t work for me?
Yes—ZenSupply offers a hassle-free return policy. If the product isn’t the right fit, reach out to our support team for a return authorization or setup a return by following our return instructions.
Does the Gardner Bender KO709 come with a warranty?
Absolutely. The Gardner Bender KO709 is backed by a manufacturer’s warranty. For full warranty terms, check the product documentation or Contact Us.
How do I get technical support or installation help for the Gardner Bender KO709?
You can call, text, or email our expert support team for fast answers. We’re here to help with product selection, installation tips, and troubleshooting. Contact Us
Why buy the Gardner Bender KO709 from ZenSupply?
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