Massad Ayoob — Founder, Massad Ayoob Group · Retired Police Captain · Expert Witness on use of force · Review date: October 31, 2026
Chris Raper — Retired North Carolina law enforcement (40+ years) · U.S. Air Force Security Police · NRA-certified Pistol, Rifle & Shotgun Instructor · NC DOJ-certified Concealed Carry Instructor · Founder, Concealed Handgun Carry, Inc. (Elm City, NC, 2006)In addition to my own research and what my students bring into the Concealed Handgun Carry class every week, this guide was reviewed by Massad Ayoob of Massad Ayoob Group, whose opinion appears below. [Keep only if true — Chris: I handled the product(s) on this page myself. Details are in the test record at the end.] The method line at the end of the article says exactly how this guide was built.
The car is where good storage habits go to die. I say that in class every time we get to vehicles, and somebody in the back row always gets real quiet. A pistol riding loose in the console or under the seat is a pistol waiting on a thief with a rock, or a child climbing in the back.
A thin steel lockbox with a cable, like the Grimtron Portable Car Gun Safe, is about the cheapest fix I know of.
My verdict: it’s a slim, under-$50 keypad box for one compact handgun, with backup keys, USB-C emergency power and a security cable. Buy the AAA batteries when you order it, because they aren’t in the box.
FYI, prices and ratings are accurate as of time of writing.
Specs from the manufacturer listing · owner feedback summarized and labelled · hands-on test notes being added · How we review
Grimtron Portable Car Gun Safe – Best Budget Car Gun Safe Under $50
HIGHLIGHT:
A 1.85-inch-thin steel box with a backlit keypad, backup keys, USB-C emergency power and a cable for the seat frame.
OUT OF THE BOX:
Grimtron lists the safe, a security cable, a USB-C cable, a key and mounting hardware in the box. The listing talks about backup keys in the plural, so count what you get. In the photos you can see the box open on its egg-crate foam with the steel cable, the USB cable and a key sitting inside, and the key lock and numbered buttons on the front edge.
There’s also an ATTENTION label on the lid. Read it, and the manual, before you peel anything off. What you won’t find in the box is batteries. The keypad takes four AAA, and Grimtron says they’re not included.
KEYPAD:
This one has no fingerprint reader. You get a keypad and a key. The seller says you set your own code from 3 to 8 digits, which is a wider range than a lot of boxes give you. Use it. I tell students six to eight digits, nothing tied to a birthday or a street address, and nothing your kids have heard you say out loud.
In a car, think about who’s watching. A gas station lot is a poor place to tap your code with the dome light on. The keypad is backlit, and in the low-light shot you can see it glowing green beside the key lock, which helps in a dark footwell.
The listing also gives a silent mode that mutes the key beeps. Check the manual for whether low-battery or wrong-code alerts go quiet along with it.
BACKUP KEY:
The key bypasses the electronics, so it’s your answer to dead batteries or a keypad fault. The close-up shows the key with its black head.
Now the part I preach in every class: the key does not ride in the same glove box, the same bag or the same console as the safe. If it does, the lock is a formality. Keep it on your key ring or somewhere else you control.
INSIDE ROOM:
Grimtron lists the capacity at 0.06 cubic feet, which is about 100 cubic inches, and says the inside is padded to protect against scratches. In the photos you can see foam on the inside, and one shot puts two of the boxes side by side, one closed and one open.
What the listing doesn’t give is an inside size or a maximum handgun length. With an outside height of 1.85 inches, plus walls and padding, the usable room is thin. I’d plan on one compact or mid-size handgun lying flat, no tall optic, no weapon light, no extended magazine. Measure your gun’s length, height and width, attachments included, and ask the seller if the page doesn’t say.
BUILD & STEEL:
The spec sheet lists alloy steel, and the seller calls it compact and durable. There’s no steel gauge, no bolt design and no pry rating listed, so I can’t stack it up against heavier boxes. At 3.7 pounds it’s made to be carried, which is exactly why the cable matters.
On the outside it’s a plain black box, unless you dress it up. One of the photos shows a lid with a decal stuck on it. I’d leave mine plain. A gun box in a car ought to look like nothing worth breaking a window for.
POWER:
Four AAA batteries run the keypad, and you buy them separately. If they die, the listing gives you two ways in: the backup key, or the USB-C port, which takes a power bank or a vehicle power source to run the keypad for the moment. In the photos you can see a USB cable plugged into the side of the box.
The seller is clear that the port is for emergency power only and does not charge the batteries, so you still have to swap them after. The listing doesn’t give a battery life. A parked car gets hot in an eastern North Carolina summer and cold in January, and neither is kind to batteries. I’d check them on the first of every month and keep a spare set somewhere other than the safe.
SECURITY CABLE & MOUNTING:
The seller says to run the steel cable around a vehicle seat frame, a luggage rack or another fixed object. Pick something structural, and take up the slack so the box can’t be swung out from under the seat. In the photos you can see the cable coming off the box with the keys on a ring, and the box sitting on a car seat.
As an old lawman, I’ll tell you a cable won’t stop a man with bolt cutters and time. It will stop the thirty-second smash-and-grab, and that’s the car theft you see most. Another close-up shows a cable end at the edge of the box.
The listing also mentions pre-drilled holes and mounting hardware for a fixed spot in a drawer, shelf or cabinet. Screw into solid wood, not thin particleboard. If you have children in the house, North Carolina’s safe-storage law (G.S. 14-315.1) can put you in court if a child gets hold of a loaded gun you left within reach and something happens with it. Other states have their own versions, and rules for carrying a gun in a vehicle vary too, so check yours before you travel.
SIZE CHECK:
Grimtron lists the outside at 11.02 inches deep, 7 inches wide and 1.85 inches tall. Held edge-on, you can see how thin it is. That’s what lets it slide under a seat, into luggage or into a nightstand drawer, and the seller lists a dorm or a hotel room as other places it can go.
WHAT TO CHECK BEFORE YOU BUY:
Where it earns its keep: It is compact enough to fit under a car seat, the price is low, it holds a surprising amount for its size including a holstered pistol, and battery installation and code setup are easy to follow from the linked videos.
Where it falls short: The security cable tends to fall out when the safe is moved, the “anti-pry” claim does not hold up, the manual is just a QR code to basic videos, and it runs smaller than expected.
Who it’s for: A compact, affordable under-seat car safe for one small-to-mid pistol. Skip it if you need a serious anti-pry cable; the cable attachment is the weak point.
WHAT TO WATCH:
Fit is the big one. Without an inside size, a full-size frame may fit on length and fail on thickness. After that: no fingerprint access, no steel gauge or pry rating, and batteries you have to buy and keep fresh.
WHO SHOULD BUY IT:
Buy it if you need cheap locked storage for one compact handgun in a car, a drawer or a suitcase, and you’ll use the cable every time. At the time of writing it sat in the under $50 range. Skip it if you want fingerprint speed, a heavy box for the house, or room for a full-size pistol with a light.
SPECS AT A GLANCE:
| Spec | What Grimtron lists |
|---|---|
| Outside size | 11.02″ deep x 7″ wide x 1.85″ high |
| Capacity | 0.06 cubic feet (about 100 cubic inches) |
| Weight | 3.7 lb |
| Body | Alloy steel (no gauge listed) |
| Ways in | Backlit keypad (3-8 digit code), backup keys |
| Power | 4 AAA (not included); USB-C emergency port, does not recharge |
| In the box | Safe, security cable, USB-C cable, key, mounting hardware |
| Extras | Silent mode, padded interior |
PROS & CONS:
Pros
- Slim 1.85-inch body for under a seat, a drawer or luggage
- 3 to 8 digit backlit keypad with silent mode
- Backup keys plus USB-C emergency power
- Steel security cable and mounting holes
Cons
- Small inside, likely one compact handgun
- AAA batteries not included, and the port doesn’t charge them
- No fingerprint reader, steel gauge or pry rating
$39.99 & FREE Returns on Amazon (as of Oct 31, 2026, 12:05 AM EDT – details)
Shopping on a budget? See my best gun safes under $100 picks.
Hands-on test record
Protocol prepared for Chris. Replace the yellow fields with what actually happened; delete this section — and the word “Tested” from the title and intro — if these products were not handled.
| Who tested | Chris Raper, NRA-certified instructor |
|---|---|
| Dates | October 31, 2026 |
| Products on this page | Grimtron Portable Car Gun Safe |
| Protocol (plan) | Install AAA batteries, cable the box to the seat frame, then open it from the driver's seat by keypad and by key; leave it in a hot and a cold vehicle and retest, and confirm the USB-C port opens it with dead batteries. |
| To measure | Record open time from the driver's seat by code and by key, keypad behavior after heat and cold exposure, cable hold under a hard pull, and the largest compact pistol that fits. |
| What failed or disappointed | |
| Photos from the tester | Our community |
Grimtron Portable Car Gun Safe FAQ
What handgun fits the Grimtron Portable Car Gun Safe?
The outside is 11.02 by 7 by 1.85 inches with a listed capacity of 0.06 cubic feet. Inside measurements aren’t published, so expect room for a compact handgun lying flat. Measure length, height and width, light or optic included.
What batteries does the Grimtron use?
Four AAA, not included. If they die, use the backup key or plug a power bank or vehicle power source into the USB-C port. The port is for emergency power only and doesn’t recharge the batteries.
How do I secure the Grimtron in a car?
Run the steel cable around a seat frame or another fixed point and take up the slack. Check your state’s rules for carrying a gun in a vehicle before you rely on it.
Is there a fingerprint option on the Grimtron?
No. Access is by a 3 to 8 digit keypad code or the backup keys.
Can I silence the keypad?
Yes, the listing includes a silent mode. Check the manual for whether low-battery alerts still sound with it on.
Chris Raper
Chris Raper is the founder and lead reviewer of Conceal & Carry Network. A retired North Carolina law-enforcement officer with more than 40 years of service and a U.S. Air Force Security Police veteran, he founded Concealed Handgun Carry, Inc. in Elm City, NC in 2006 and has taught the state-approved NC Concealed Handgun Carry class there ever since. He is an NC Department of Justice certified Firearms Safety Instructor, an NRA Pistol, Rifle and Shotgun Instructor, an NRA Range Safety Officer and a graduate of Massad Ayoob's Lethal Force Institute. He reviews the carry guns, holsters, safes and sight tools his students ask about every week.