Does it work on any vehicle?

It needs a large flat metal surface such as a roof or trunk lid to grip and ground. Fiberglass, aluminum and plastic panels will not work without a ground plane.

Is it good for weather band?

Yes. It covers the NOAA weather channels along with CB, so you can check road and storm conditions.

Will it damage my paint?

The base has a scratch-resistant pad, but grit trapped under the magnet can still mark the finish. Wipe the surface and the pad before each mount.

How does it compare with a permanent mount?

A drilled NMO mount usually gives a better ground and a cleaner signal. This magnet mount trades some performance for easy removal and no holes.

Can I use it with a 10-meter radio?

It is tuned for CB and 10-meter use, but check the SWR before transmitting. You may need to trim the whip for the best match.

Where is the Cobra 42" 300-Watt Magnet Mount Antenna cheapest?

At Walmart, for $49.95, as of our latest check.

What do buyers say about the Cobra 42" 300-Watt Magnet Mount Antenna?

Rated 4.3 out of 5 from 146 ratings.

Where can I buy the Cobra 42" 300-Watt Magnet Mount Antenna?

4 stores we checked sell it, including Best Buy, Cobra, NAPA, Walmart.

Cobra 42" 300-Watt Magnet Mount Antenna

Best price now

$49.95at WalmartChecked 10 h ago

Compared across 4 stores. Prices are checked against each store and labelled with when.

Visit Walmart

Cobra 42" 300-Watt Magnet Mount Antenna

Best price now

$49.95at WalmartChecked 10 h ago

Compared across 4 stores. Prices are checked against each store and labelled with when.

Visit Walmart

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Price facts

Lowest price today: $49.95 at Walmart (checked Nov 10, 2026).
Checked at 4 stores.

Our take on the Cobra 42" 300-Watt Magnet Mount Antenna

This is a base-loaded CB and 10-meter antenna on a large magnetic mount, with a stainless steel whip and a scratch-resistant base pad. It is meant to be stuck on a metal roof or trunk and removed when not in use, so it suits drivers who want CB or weather-band reception without drilling holes. The 42-inch whip gives it more reach than short stub antennas, though a permanent NMO mount will usually outperform any magnet mount. Owners rate it well overall, with the usual complaints about magnet-mount grounding and wind noise at speed.

Best forDrivers who want temporary CB or 10m setup with no drillingTruckers and road-trippers checking weather-band broadcastsBuyers wanting a stainless whip that resists rustOccasional users who move the antenna between vehicles

Pros

Large magnet base holds firmly on flat metal
Stainless steel whip and hardware resist corrosion
Scratch-resistant pad protects paint
Covers CB channels plus weather band
Simple install with no tools or drilling

Cons

Needs a large flat metal surface to ground well
Tall whip catches wind and low clearance
Not as strong a signal as a drilled permanent mount
Coax length limits where you can place it

Cobra 42" 300-Watt Magnet Mount Antenna prices at every store

Best BuyNew
In stock
$49.95Free shippingChecked 10 h ago
Visit Best Buy
CobraNew
In stock
$49.95Checked 10 h ago
Visit Cobra
WalmartNew
In stockSold by Cobra I Escort I CedarReturns: Sold by a Walmart Marketplace seller; returns go to the seller under the seller's returns policy.
$49.95Free shippingChecked 10 h ago
Visit Walmart
NAPANew
In stock
$52.99Checked 10 h ago
Visit NAPA

Store links may earn us a commission. Some prices via Klarna.

Cobra 42" 300-Watt Magnet Mount Antenna price history

Lowest price we've seen: $49.95 on Nov 10 at Best Buy. Tracked across 3 stores since Nov 10.

What reviewers say

4.3 / 5146 ratings

Owners rate it 4.3 out of 5 and mostly praise the strong magnet, easy setup and solid reception for the size. Complaints center on grounding problems on some vehicles and wind noise or sway from the tall whip.

What people mention

Magnet strengthPraisedOwners say the large base stays put on the roof or trunk even at highway speed.
ReceptionMixedMany report clear CB and weather-band reception, but some get static or poor range when the mount does not ground well.
BuildPraisedThe stainless whip and hardware are described as sturdy and rust-resistant.
Wind noiseCriticisedThe 42-inch whip sways and whistles at speed, which some drivers find distracting.
HeightCriticisedOwners note the tall whip hits low clearance in garages and drive-throughs.

About the Cobra 42" 300-Watt Magnet Mount Antenna

The Cobra 42" 300-watt Magnet Mount Antenna is a convenient tool for CB and 10m radio enthusiasts. It's designed for a simple, easy installation that works with any vehicle. This Cobra antenna features a base-load large magnet mount design. Its whip and hardware are made from durable stainless steel, and it sports a sleek black finish. This item is optimized for enhanced signal reception to help you enjoy even distant broadcasts. Its weather-band compatibility is a valuable safety asset for drivers, giving you a fast and easy way to check on road conditions. This Cobra antenna has a scratch-resistant base pad to protect your car's finish. With this product, you will find that you are able to access a wide range of communications. This CB radio antenna's straightforward design and easy installation make it an efficient addition to your vehicle setup.

Specifications

color: BlackSource
size: 38.00" x 6.00" x 3.00"Source

Questions and answers

Does it work on any vehicle?: It needs a large flat metal surface such as a roof or trunk lid to grip and ground. Fiberglass, aluminum and plastic panels will not work without a ground plane.
Is it good for weather band?: Yes. It covers the NOAA weather channels along with CB, so you can check road and storm conditions.
Will it damage my paint?: The base has a scratch-resistant pad, but grit trapped under the magnet can still mark the finish. Wipe the surface and the pad before each mount.
How does it compare with a permanent mount?: A drilled NMO mount usually gives a better ground and a cleaner signal. This magnet mount trades some performance for easy removal and no holes.
Can I use it with a 10-meter radio?: It is tuned for CB and 10-meter use, but check the SWR before transmitting. You may need to trim the whip for the best match.
Where is the Cobra 42" 300-Watt Magnet Mount Antenna cheapest?: At Walmart, for $49.95, as of our latest check.
What do buyers say about the Cobra 42" 300-Watt Magnet Mount Antenna?: Rated 4.3 out of 5 from 146 ratings.
Where can I buy the Cobra 42" 300-Watt Magnet Mount Antenna?: 4 stores we checked sell it, including Best Buy, Cobra, NAPA, Walmart.

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