The K40 RLS2 Radar/Laser Detector Will Keep the Tickets at Bay

Some people habitually drive too fast. For them, a good Radar Detector is a great way to keep tickets at bay. For me, however, a good radar detector is an effective reminder to pay attention and watch my speed. The K40 RLS2 Radar/Laser Detector is just such a tool, and it is an impressive one for speed demons and for me!

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Judie recently reviewed K40’s remote installed radar detection systems. It required a professional installation and, as she showed in her review, it does an amazing job of letting you know when radar is going to be on you long before you actually have a “problem.”

The company’s high-performance RLS2 radar detector that I was sent for review takes a different approach. While still packing the “powerful defensive punch” of the installed unit, it comes in a convenient, portable design. The unit installs in seconds and, because it is portable, it can be moved from one car to the other with ease. Better still, with this unit one avoids the process of having the unit professionally installed.


As the company explains:

Maximum accuracy is assured thanks to the intelligent K-Band filter that automatically scans and rejects radar-based safety features. With a variety of audible and visual warnings that warn what type of threat you’re facing as well as “geiger” audio effect that increases in intensity, you’ll be armed with maximum critical information so you can decide what action is required.

The unit ships with everything you need to install the RLS2 in just about any car. You get the unit itself, a fully adjustable windshield mounting bracket with suction cups, a standard coiled power cord with 12V outlet adapter, and a straight power cord for a custom hardwired installation. All of this means you can mount it in one car and then, if you upgrade your vehicle, simply move it from the old car to the new one. It also works well if, for example, you are taking a road trip. But I’m getting ahead of myself.


The portable device employs state-of-the-art GPS communication so you will always get maximum protection. It also offers the convenience of “Mark to Mute”. With this feature all it takes is a single press of a button to permanently silence the audio warning of false warning locations. This is important since, as I discovered while testing the unit, there are specific places I pass regularly that serve up a warning despite the fact that there is never an active radar detection system locking onto my car. Without the “Mark to Mute” function, these locations could trigger a warning each and every time I passed by. Thanks to this feature these “false warning locations” can be permanently turned off without my having to lose the protection the unit is designed to offer.

The system also offers 13 customizable settings so you get maximum control over the driving experience. Let’s run down the features and then talk about my experience using the K40 RLS2 Radar/Laser Detector.

  • K-Band Filter– An advanced, automatic filtering technology that intelligently recognizes and rejects radar-based safety features (such as adaptive cruise control or blind spot assist) in other vehicles so you can remain focused on real radar threats.
  • Traffic Sensor Filter– Your RLS2 will reject alerts from traffic flow sensors usually encountered during highway driving.
  • Mark to Mute– By using sophisticated GPS technology, you can easily program your system to mute the audible warning of false, non-police radar locations (e.g. an automatic door) you regularly travel past with a simple button push.
  • 13 Customizable Settings– No two drivers, vehicles, or driving environments are the same. The K40 RLS2 is completely customizable to the way you drive.
  • Flexible Mute options– Offers multiple ways to silence alerts, including automatic volume reduction.
  • Dim– Adjust the intensity of the display depending on the time of day or your visual preference.
  • GPS-based “Mark to Alert”– Mark to alert for locations such as speed traps, school zones, or red light cameras. This feature gives you the ability to “Mark and Unmark” any location. Build your own database of locations that are important to you. No annual subscriptions and no downloading or updating an ever-changing database from a home computer or laptop.
  • Quiet Ride– Eliminate annoying alerts in areas with a high concentration of non-police radar sources such as a strip mall parking lot. Just set a minimum detection speed and all audible alerts are eliminated until your vehicle exceeds a defined speed.
  • Speed Monitor– The next best thing to having a vigilant co-pilot riding with you. Whenever a preselected speed is exceeded, a constant audible alert is activated along with a visual alert advising you to “slow down.”
  • Fully Programmable Radar/Laser Alert Options– Enables you to eliminate audible and visual alerts to specific radar bands or laser.
  • Voice or Tone plus Digital Display– Unique audible and visual warnings alert you to the specific police radar band targeting your vehicle as well as provide a “geiger” audio alert that accelerates as you near the threat.
  • Vibrant Dot Matrix Display– Great looking and easy to read, day or night. Easily adjust the brightness to suit your driving environment. Default display shows your filter setting, compass direction, and speed reading.

As you can see, the K40 RLS2 Radar/Laser Detector has some amazing features, and it really packs a ton of power into a small, portable unit. I used it at home a bit, but then decided to really test it out in the best way possible… on a road trip out west!


I spent the second week of July in Israel and then flew directly to LA from there. Raina, who was not on the trip to the Middle East with me, went from New Jersey to LA a few days before I arrived. She packed the K40 Radar Detector in her bag so I could avoid having to bring the unit with me on my initial travels. (Israeli security tends to be rather tight, and I really did not want to end up explaining why I, who was with a group and taking private charted buses everywhere, had a radar detector with me.) I landed in LA, and Raina picked me up in a rented Hyundai Sonata. I pulled the radar detector out and plugged it in. The entire installation, if you can call it that, took about three seconds. I adjusted the volume and we began to drive.


The first leg of our trip was LA to Las Vegas. We let the radar detector do its thing and simply adjusted the volume so we didn’t have to hear it constantly. Honestly, that wasn’t a huge concern because the detector put out far less phantom alerts than any detector I have used. I quickly got to the point where I trusted that, if an alert went off, there was a reason for it. Almost always… there was.

That, of course, is thanks to the K-Band Filtering

While we were in Los Angeles, I knew we would have a good deal of stop and go traffic. The Quiet Ride function came in quite handy! Seriously, think about what a brilliant setting this is. When I know I will be starting and stopping or moving at a fairly low-speed, there is no reason to get alerts. The Quiet Ride feature lets you set the detector to only alert you when you have reached a certain speed and, as a result, may be tempted to go even faster.


The Vibrant Dot Matrix Display is a second aspect of the K40 that came in quite handy. The display is easy to read, and I quickly came to rely on it for information us of our direction (compass) or speed. It is, as advertised, easy to read, day or night, and I was able to adjust the brightness so it was easy to read but not a distraction.

I should note that, while in California, we simply set the detector on the dashboard rather than using the included suction windshield mount. The reason for this is that, while California allows radar detectors, they do not allow anything to be mounted on the windshield. It was simply easier to leave it sitting on the dash in order to avoid any potential issue.


The next leg of the trip took us to the Grand Canyon. When we headed from Las Vegas to Williams, Arizona we found the highway speeds becoming increasingly high. I had never before encountered legal speeds limits of 75 miles an hour and I loved it! Here’s the thing though, the Sonata is a fantastic car. (Yes, I love my Lexus, but I was so pleasantly surprised by how great the Sonata was.) It also handled going 75 miles an hour with ease. In fact, not that would know from first-hand experience, but it handles speeds far in excess of 75 miles an hour without issue. 🙂

And I was concerned. When speed limits are as high as 75 miles an hour, I suspect the tolerance of the highway patrol is far less for those who even exceed THAT. And even if traffic was going far faster than 75 miles an hour, I figured 79 was safe but going much over 80 could be an issue. That’s where the radar detector’s Speed Monitor came in.

The next best thing to having a vigilant co-pilot riding with you. Whenever a preselected speed is exceeded, a constant audible alert is activated along with a visual alert advising you to “slow down.”

I set the top speed that I thought would be reasonable and, from there, simply drove. Whenever I exceeded my set speed, I got a gentle reminder that I might want to reconsider. As a result, we were able to cover hundreds of miles in a bit less time but without the worry of getting pulled over.

All the while the K40 RLS2 Radar/Laser Detector gave few if any false alerts. When an alert did happen, we almost always saw the source and were grateful to have the protection it offered.


The last leg of our trip brought us into Utah. We stayed at a resort about an hour and a half from both Zion National Park and Bryce Canyon National Park. That meant we had a few days with a good bit of driving during each. Again, having a radar detector as an additional layer of information and “safety” was pretty great.

Best of all, when we turned in the rental, all I had to do was unplug the device from the power port and put it in my bag. Now we are back home, and it has once again taken up residence on my Lexus’ windshield.

In all, this is an incredibly power radar detector that is also simple to set up and use. I’m a fan.

You can check it and all the offerings from K40 out here on the company website.

Source: Manufacturer supplied review sample of the K40 RLS2 Radar/Laser Detector

What I Like: Simple to install; Packed with features; Easy to use; Easily moved from one vehicle to another

What Needs Improvement: Nothing

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About the Author

Dan Cohen
Having a father who was heavily involved in early laser and fiber-optical research, Dan grew up surrounded by technology and gadgets. Dan’s father brought home one of the very first video games when he was young and Dan remembers seeing a “pre-release” touchtone phone. (When he asked his father what the “#” and “*” buttons were his dad said, “Some day, far in the future, we’ll have some use for them.”) Technology seemed to be in Dan’s blood but at some point he took a different path and ended up in the clergy. His passion for technology and gadgets never left him. Dan is married to Raina Goldberg who is also an avid user of Apple products. They live in New Jersey with their golden doodle Nava.