Top 5 Best Catalytic Converter Shield Reviews • (2024 Guide)

Last updated Feb 15, 2024

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Catalytic converter theft is no joke, just ask these people. Thieves are more than aware of the fact that catalytic converters contain precious metals that they can profit from. Because of this, car owners are beginning to invest in the best catalytic converter shield to protect their investments. However, not all car owners were created equal in this field.

There are two car owners in particular who get targeted by catalytic converter thieves. Those are Prius and Honda Element owners, with the former being the most heavily targeted. Chances are that since you’re here right now, you’re the proud owner of a Toyota Prius. The good news is that the products below will fill your order for the best catalytic converter anti-theft device.

First, let’s take a look at your available options before going over what to expect from each shield in the reviews.

Top 5 Catalytic Converter Anti-Theft Devices

Product Description
#1) MILLERCAT Cat Shield

  • Material: Aluminum, Stainless Steel
  • Car Compatibility: Prius, Sequoia, Tacoma, Tundra, Element
  • Dimensions: 23″ x 20″ x 2″ (LxWxH)
  • Weight: 15 lbs
  • Model: PG3
  • Price: $$$
  •  Coupon Code 5% Off:  THEFTBOSS
#2) Cap City Muffler Cat Security Cat Shield

  • Material: Aluminum
  • Car Compatibility: Prius, Sequoia, Tacoma, Tundra, Element, Chevrolet City, Nissan NV 200
  • Dimensions: 24.5″ x 19″ x 0.5″ (LxWxH)
  • Model: CAT-SCR-GEN4
  • Price: $$
#3) Caramore Catalytic Converter Protection Shield

  • Material: Aluminum
  • Car Compatibility: Prius
  • Dimensions: 24.2″ x 19″ x 1″ (LxWxH)
  • Weight: 4.09 lbs
  • Model: ‎KMT-OT00581
  • Price: $
#4) Mr Repair Parts Cat Converter Protector

  • Material: Aluminum
  • Car Compatibility: Prius
  • Dimensions: 29″ x 23″ x 2″ (LxWxH)
  • Weight: 4 lbs
  • Model: HOKE-P1620
  • Price: $
#5) CAT GUARDIAN for Honda Element

  • Material: Aluminum
  • Car Compatibility: Honda Element
  • Price: $$$$

Best Catalytic Converter Shield Reviews

Now that you’ve had the chance to check out the top catalytic converter anti-theft device, it’s time to go a step further. Mainly, there are two brands that carry the torch, and those are the first two listed. By choosing one of the best cat shield brands, you’ll have a greater variety to choose from. As a result, more than just Honda Element and Toyota Prius owners will find value.

Other car owners that may want to add a cat shield are Toyota Tundra, Sequoia, and Tacoma owners. With that being said, always make sure to match your year and model to the right cat shield. The model #s listed above are for certain models in particular. Once you match your model to the correct shield, you’ll find that there are shields for 2001 Gen 1 Prius owners all the way up to the present.

#1) Cap City Muffler Cat Security Cat Shield

First up, you have Cap City Muffler, which is a good balance between price and availability. On average, Cap City Muffler shields are slightly more affordable than comparable Millercat models. However, the main difference between Cap City and Millercat is that Cap City shields are all made of aluminum. On the other hand, Millercat offers both stainless steel and aluminum models.

Beyond that, Cap City is in the driver’s seat when it comes to designing cat shields. You’ll find that the company’s most popular models are all made for the Toyota Prius, which is the most targeted vehicle by thieves. One interesting option for certain Prius owners is the Level 2 Ultimate Protection kit. This particular kit comes with steel reinforcements to further thwart thieves.

After those considerations, the shields are made of corrosion-resistant lightweight aluminum with optimal ventilation placement. The installation does not require welding, but it is recommended to go with a professional installation. Lastly, the laser-cut shield protects both your catalytic converter and your O2 sensor.


  • A vast range of shields to choose from for a variety of car models
  • The ability to upgrade to ultimate protection for Prius owners
  • Laser-cut aluminum for a precise fit
  • Optimal ventilation placement
  • No-welding-required installation
  • Hardware included


  • Likely to require additional parts for installation
  • Some models are prone to rattling without professional installation
  • Instructions could be better for DIYers

#2) MILLERCAT Cat Shield

For DIYers and people who enjoy variety alike, Millercat is the best catalytic converter shield. As mentioned previously, you have the option to choose between aluminum and stainless steel models. Keep in mind, stainless steel models will always cost more. So there’s the need to compare the overall cost of the shield & installation to your catalytic converter replacement cost in the event of a theft.

The Millercat design team thought of every possibility when constructing its shields. There’s precise ventilation placement, a bottom lip to prevent rear pipe cutting, and even clear visibility for smog techs to read the part number. Beyond that, the kit includes just about everything you need for installation, including the shield, hardware, screw kit, sticker, and installation guide.

Next, what really sets Millercat apart from its competitors is its other products category. Millercat also offers a deadbolt for ultimate security and a manual rivet nut tool for car owners who prefer to do the installation themselves. Because of this, handy car owners can save a good chunk of change by doing the installation on their own. In turn, the money saved can be used to upgrade to a Millercat Deadbolt and new exhaust hangers.


  • The best choice for DIYers and handy car owners
  • Designed with every possibility in mind
  • A wide range of models to choose from for Toyota car owners
  • Optional accessories for enhanced security
  • Stainless steel models are available
  • Clear installation instructions


  • The slightly higher upfront cost
  • Costs can get high with professional installation
  • Rattling may occur in some car models

#3) Caramore Catalytic Converter Protection Shield

For those Prius owners who prefer a budget catalytic converter shield to act as a deterrent, Caramore is a solid brand. Currently, Caramore only offers shields for Prius owners. There are models to fit Prius models manufactured in 2004 all the way up to the present. Comparatively, Caramore shields are significantly more affordable than models by Cap City Muffler and Millercat. In fact, the cost of the shields designed for Prius models from 2016 to the present cost almost nothing.

For this reason, if you plan to go with a professional installation, most of the cost will go toward the installation than the shield itself. However, this goes back to calculating how much you value your catalytic converter vs the cost of the shield plus installation. Beyond those considerations, Caramore shields are made of aluminum, and they weigh less than the first two brands.

Finally, it’s important to note that Caramore shield installation may get complicated for some DIYers. So if you choose to take the DIY route, you’ll want to have some automotive experience under your belt for a proper installation. Other than that, Caramore shields do come backed by a 60-day warranty window should you run into any issues.


  • A good budget alternative to Millercat and Cap City Muffler
  • Unlikely to rattle
  • Available for Prius models starting in 2004 to present
  • Installation instructions are available online
  • 60-Day Warranty


  • Limited to Prius models only
  • Professional installation is most likely required
  • Additional installation costs

#4) Mr Repair Parts Cat Converter Protector

Are you still interested in taking the budget route? If yes, then Mr Repair Parts shields are another viable budget option. Consequently, you’ll find much of the same offered by Mr Repair Parts as you would from Caramore. Firstly, like Caramore, Mr Repair shields are made specifically for Prius owners.

At the time of this writing, Mr Repair offers shields for Prius models ranging from 2004 to 2020. Comparatively, the selection is not quite as great as Caramore, hence why we ranked Mr Repair after Caramore. Additionally, at the time of this writing, Mr Repair shields are selling for more than Caramore models.

As for materials and construction, one of the greatest advantages of choosing Mr Repair shields is that they’re made in the USA with 100% aluminum. This feature alone may be the greatest selling point for some to avoid overseas quality control issues. The kit itself does include the required hardware, though, Mr Repair recommends professional installation for all of its cat shields.


  • Made in the USA
  • 100% high-quality aluminum construction
  • Available for early Prius models
  • Heat extraction vents
  • Hardware kit included


  • Available for Prius only
  • Professional installation recommended
  • Additional installation costs

#5) CAT GUARDIAN for Honda Element

Last up is an alternative option for Honda Element owners. Presently, this particular Cat Guardian model is available for Honda Element models manufactured between 2003 and 2011. Having said that, your heart better be set on this particular shield because the current cost eclipses what’s offered by our top two selections on this list.

As you can see from the photo, the Honda Element shield is a much different design than a Prius shield. The Element shield is deeper with a larger opening at the top. Highlights of the Cat Guardian model include aluminum construction, no-cutting-required installation, and installation hardware included.

Should you choose to install the shield yourself, keep in mind that the kit does not include the rivet tool. Ultimately, you’ll more than likely want to hire a professional to do the installation for you to avoid any problems while on the road such as rattling.


  • A good alternative for Honda Element owners who are having trouble finding a shield
  • Includes required installation hardware
  • Installation requires no cuts
  • Designed for maximum coverage


  • Higher upfront cost at the time of this writing
  • Less proven brand


Below, we address common questions related to catalytic converter theft and ways to prevent catalytic converter theft for car owners with targeted vehicles.

Do catalytic converter shields work?

Yes, they do. Yet, it’s important to get a clear idea of “work” in this circumstance. Since a skilled thief can nab a converter in just minutes without a shield, a shield adds an extra layer of security. Similar to a secure padlock, a shield requires the thief to do a more intricate theft, which adds time and the need for additional tools.

Because of this, shields are more than just deterrents. Comparatively, your catalytic converter is a lot safer than for someone who doesn’t own a shield. With that being said, it’s still wise to park your car in a garage overnight and in public areas when out during the day to avoid thieves altogether.

How do thieves steal catalytic converters?

Essentially, a thief will slide beneath your car to access the exhaust system and use a saw to cut out the catalytic converter. Amazingly enough, the process can take just a few minutes since cars aren’t designed to prevent cat converter theft.

Which cars are most likely to have catalytic converters stolen?

The #1 target among thieves is the Toyota Prius, and this happens to all years of the Prius, particularly older models. In addition to the Prius, other Toyota models are heavily targeted, including Tacoma, Sequoia, and Tundra. Honda Element, Lexus SUVs, and other similar models may also fall victim to catalytic converter theft.

Why are Prius catalytic converters stolen?

Thieves are capitalizing on the rise in the value of precious metals contained in catalytic converters including platinum, rhodium, and palladium. Older Prius models fetch the most money because of the additional precious metals in their converters. Plus, the fact that the Prius doesn’t get as hot keeps the quality of the metals intact. In recent years, catalytic converter theft in older Prius models has skyrocketed.

How much do thieves get for stealing a catalytic converter?

The sad part is that thieves only sell the converters for upwards of $300 to scrap yards. Keep in mind that the replacement cost of a converter can cost several thousand. Clearly, converter theft is not the most profitable side hustle, but for thieves who make it a daily job, it can be a lucrative business.

How do you know your catalytic converter was stolen?

The telltale sign of catalytic converter theft is that your vehicle will suddenly become obnoxiously loud. For sure, you’ll be able to hear the difference. Also, you may notice the check engine light. In severe cases, you may experience a headache due to increased exposure to carbon monoxide.

Bottom Line

With the recent rise in catalytic converter theft, all Prius owners should consider adding the best catalytic converter shield to their anti-theft arsenals. Currently, the two leaders in the shield space are Millercat and Cap City Muffler. To make your final decision easier, compare the prices between the two brands and speak to your mechanic to get an installation quote. Also, your mechanic may already have experience installing shields manufactured by one or both brands.

You may also be interested in our related article: Best Car Alarm for Catalytic Converter Theft

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