Defender Harness System

One complete system for safer car rides and everyday adventures
Price
Regular price $224.99
Regular price $324.99 Sale price $224.99
Save $100
/

Canadian Inventory Sale:

Save on select sizes and colours from our existing Canadian inventory. Once these units sell out, regular pricing returns.

Your Defender system includes

  • Defender Harness System
    Harness
  • Defender Upper Tether
    Upper Tether $39.99 value
  • Defender Lower Tether
    Lower Tether $44.99 value
  • Leash Converter Free
    Leash Converter $29.99 value
Size
Colour Camo
Shipping calculated at checkout.

Made in Canada•60-Day Fit Guarantee

Description

Designed for ease of use, comfort, and maximum protection, these Defender Harness Systems securely anchor your dog in any vehicle while ensuring a snug, ergonomic fit. Proudly made in Canada, they provide the peace of mind that your pet is just as safe on the road as you are.

What’s Included:

  • Defender Harness

    Defender Harness: The wearable harness for walks and car travel.

  • Upper Vehicle Tether

    Upper Vehicle Tether: Connects the harness to your vehicle’s seatbelt.

  • Lower Vehicle Tether

    Lower Vehicle Tether: Helps position your dog in the seat.

  • FREE Leash Converter

    FREE Leash Converter: Connects your leash to the harness for walks.

60 Day Fit Guarantee

Try it at home and make sure it works for your dog.

If it is not the right fit, you can return it within 60 days.

We will also work with you to adjust sizing or setup before you need to return it.

View full return policy

Crash Replacement Guarantee
Crash Replacement Guarantee

If your harness is ever involved in a vehicle collision, we will replace it.

We will also cover shipping both ways.

We may ask for a few details about what happened so we can continue improving the system.

Learn more about our crash replacement guarantee

Shipping Information

Canada: Free shipping

International: If an estimated shipping cost is not displayed at checkout, please email contact@optimusgear.com for a quote.

U.S. Shipping Update

New U.S. tariffs may apply to certain Canadian-made products, including dog harnesses. We temporarily paused U.S. shipping because we did not want customers receiving unexpected charges when their orders arrived.

U.S. shipping is now available on a limited test basis while we verify our automatic duty calculations. Any estimated duties and import taxes will be shown at checkout. During this testing period, Optimus Gear will cover any unexpected difference in duties assessed after purchase.

Pairs Well With

Size Guide

Measure your dog before selecting a size.

Measure neck circumference (A) and chest circumference (B)

Compare your measurements

  • X-Small

    Neck (A)
    Contact
    Chest (B)
    Contact
    Crash rated
    15 lbs
  • Small

    Neck (A)
    13-16”
    Chest (B)
    21-25”
    Crash rated
    25 lbs
  • Medium

    Neck (A)
    14-18”
    Chest (B)
    25-31”
    Crash rated
    45 lbs
  • Large

    Neck (A)
    17-20”
    Chest (B)
    28-38”
    Crash rated
    75 lbs
  • X-Large

    Neck (A)
    19-26”
    Chest (B)
    30-40”
    Crash rated
    85+ lbs

Need a custom size?

Email contact@optimusgear.com with your A and B measurements and your dog’s weight.

Download the Defender Harness Sizing Guide (PDF)

Unsure about your dog’s fit?

Our team can review your dog’s information and recommend the right Defender size. If adjustments are needed, we’ll make them at no extra cost. You can even start without your dog present.

Start the fit process

Crash-Tested. Independently Tested.

The Defender Harness System has undergone independent dynamic sled testing using protocols derived from FMVSS / CMVSS 213 child restraint testing standards—evaluating system integrity, load distribution, and hardware retention under simulated collision conditions.

Successfully tested in XS, S, M and L.
XL testing is planned for the next scheduled test run.

See How It’s Tested

How it works

From the sidewalk to the back seat.

Your dog wears the same harness for walks and car rides. The included attachments let you switch between the two.

Complete Your Setup

Black dog in a blue Defender harness sitting on a grey Quick Guard seat cover in the back seat of a car

Room to Settle In

Dogs can sit, lie down and adjust their position while properly connected to the Defender System.

Sit Comfortably
Lie Down
Adjust Position

FAQs

Is the Defender a walking harness or a car harness?

Both. Your dog wears the Defender for walks and car rides. Use the leash converter for walking and both vehicle tethers for car travel.

What comes with the Defender System?

Everything for walks and car rides:

  • Defender Harness: The wearable harness for walks and car travel.
  • Upper Vehicle Tether: Connects the harness to your vehicle’s seatbelt.
  • Lower Vehicle Tether: Helps position your dog in the seat.
  • FREE Leash Converter: Connects your leash to the harness for walks.
How does it connect to my car?

Step 1: Attach the Upper Tether

Open the carabiner on the Upper Tether and clip it around the active (moving) portion of your vehicle’s seatbelt.

Close and lock the carabiner fully.

Step 2: Secure the Lower Tether

The installation method depends on your dog’s harness size.

For XS, Small, and Medium Harnesses

Insert the seatbelt receiver on the Lower Tether into the seatbelt buckle, just like buckling your own seatbelt.

  • The vehicle seatbelt itself should remain unbuckled
  • You’ll hear a click when it’s properly engaged

For Large and XL Harnesses

Locate your vehicle’s child seat anchors (UAS / LATCH anchors) in the back seat.

  1. Place the UAS connector over the metal anchor bar
  2. Pull firmly toward you until it locks into place
  3. Repeat on the other side

You should feel both connectors seat securely.

Step 3: You’re Ready to Ride

Once both tethers are secured, your dog is safely installed and ready for the drive.

Before driving, always double-check that all connectors are fully locked and secure.

Prefer to Watch Instead?

If you’d rather see the installation step by step, watch our short setup video below:

▶ Watch the Installation Video

https://youtu.be/Aq2umgMay0g?si=7JmCKoCysYfJOznO

Download the Defender Harness Installation & Use Instructions (PDF)

Can my dog sit or lie down while connected?

Yes! The Defender harness allows your dog to sit or lay down comfortably while still being securely restrained. The lower tether helps keep them stable, preventing them from shifting too much during the ride. This setup ensures both comfort and safety.

Can I use it in more than one vehicle?

Absolutely! If you frequently switch between vehicles, we recommend using a second tether system instead of purchasing multiple harnesses. This allows for quick and easy transitions while maintaining safety.

What if I’m unsure about the fit?

Not sure which size your dog needs? Our team can help you choose a Defender and understand how to set it up.

With our 60-Day Fit Guarantee, you have time to check the fit at home. If something isn’t right, talk to us—we’ll help with sizing or setup and explain your return options.

What happens if my Defender is involved in a crash?

If your harness is ever involved in a vehicle collision, we will replace it.

We will also cover shipping both ways.

We may ask for a few details about what happened so we can continue improving the system.

Learn more about our crash replacement guarantee

Small dog in a Defender harness on a seat cover in the back seat, owner beside them

For the drive there, and the walk when you arrive.

One harness for both, with two vehicle tethers and a free leash converter included.

Made by us in Winnipeg, Canada.

Shop the DefenderQuestions?

Talk to our team