Lockoffs and Belt Tensioners for Easy Installation of Carseats

What Are Seat Belt Lockoffs and Belt Tensioners for Carseats?

Seat belt lockoffs have been on carseats for decades (yes, literally, thanks to Britax!), making installation so much easier. They are a premium feature, so you do pay more for them; very basic carseats won’t have such niceties, though some manufacturers are putting these features on more affordable models.

Now belt tensioners have also hit the market in recent times and wow, let’s start doing happy dances for those suckers! When I see a belt tensioning device on a carseat, I know my carseat installation will be effortless, or nearly so.

You may be wondering what the difference is between a lockoff and a belt tensioner. Maybe you thought they were the same thing. Maybe you don’t actually know what either are and are curious why I’m singing their praises. Whatever your reason for being here, let’s give meaning to these words.

What Is A Lockoff?

A lockoff locks your seat belt for you. The seat belt—actually the lap belt portion—must be locked tightly against the carseat for it to be safe. This can be accomplished in 3 ways: the retractor can be locked, the latchplate can be locked, or you can use a device (either a locking clip—yuck!—or a lockoff). Many caregivers don’t know how to lock either their retractor (about 95% of vehicles have this) or their latchplate (if it’s the kind that locks), so this becomes a very confusing thing. Enter the lockoff.

Types of Lockoffs:

Slide: With this lockoff, you slide the seat belt, usually the shoulder belt on the side opposite of the buckle, into the lockoff. I find this type typically takes some practice for first-timers because you have to hold tension in the shoulder belt as you slide it into the lockoff.

Clamp: This type of lockoff can be a barrette-style or a ski boot/cycling shoe-style clamp that clips over the top of the seat belt. It’s more intuitive, but caregivers need to remember to open both sides before placing the seat belt in it.

Belt Tensioner: A belt tensioner does what its name suggests: it tightens the seat belt for you with little effort (OMG yay!). It uses a channel(s) and presses the belt mechanically into this channel to create the tension (in a serpentine snake-y way). It uses leverage to make the job easier and whenever you see the word “leverage” used with carseats, you know there’s less work involved.

https://youtu.be/ASKRvkTsS5Q

Can a lockoff be a belt tensioner and vice versa?

YES!

How will I know if a lockoff is a belt tensioner or if a belt tensioner is a lockoff?

In the owner’s manual, after closing the lockoff or belt tensioner panel/door, the instructions will tell you to lock the seat belt. If you *must* manually lock the seat belt, you know that the lockoff or belt tensioner is NOT a lockoff that locks the seat belt.

Can I use a lockoff or belt tensioner with LATCH?

Maybe. I know it’s frustrating that there isn’t an across-the-board answer or rule that we can follow, but we all have to read the owner’s manual for each carseat to find this information (even CPS techs!). Some seats allow the lower LATCH connectors to be used with the lockoff or belt tensioner panel/door, while others don’t (I mean, it would be near impossible to get the LATCH straps through the Chicco KeyFit lockoffs, though I’m sure some of you have tried ?).

Is it better to have a lockoff or belt tensioner if the carseats I’m comparing don’t have both?

It depends on how you’ll be using the carseat. Both features are pretty handy and if you’ll be moving your carseat frequently, you’ll really want to find one that has both, like a Britax ClickTight or Graco SnugLock. The belt tensioner makes the install easy while the lockoff removes that extra step of locking the seat belt you may forget *that one time*.

If you’ll be flying with the carseat, especially if you’re going to outside the U.S./Canada, you’ll probably want a carseat that has a lockoff since you won’t know how the rental/destination vehicle seat belts lock. If you can avoid dealing with a locking clip while traveling out of the country, it’s worth it!

Which carseats have a lockoff or belt tensioner?

Check out the list below. And when you’re in the store, look under the cover in the belt path. You now know that it’s a belt tensioner if it has a channel where it forces the belt into a groove. Read reviews at TheCarSeatPros.com: we’ll tell you in the features section if the carseat has it. Read the owner’s manual online before you buy—that’s also a great way to know how to wash the cover and make basic adjustments when you get the seat out of the box.

Lockoffs and belt tensioners are great premium features that help you install your carseat. Manufacturers put them on more models every year. If you move your carseat from vehicle to vehicle frequently, you may want to look for one that has one of these built-in to make life easier. Having a carseat without a lockoff or belt tensioner isn’t the end of the world by any means, but they sure are nice.

2025 List of Carseats that Have Lockoffs and Belt Tensioners

Unless otherwise specified, the device is a lockoff. If the device is a belt tensioner only, it will be marked with a ^{BT only}. If the lockoff is available for forward-facing use only, it will be marked ^{FF only}. If the device is both a lockoff and a belt tensioner, it will be marked ^BOTH.

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Baby Jogger

City GO 2^BOTH

City Turn^BOTH

Britax

Cypress

Willow Aspen sold in Willow Brook Travel System^BOTH

Willow S^BOTH

Poplar ClickTight^BOTH

Poplar S ClickTight^BOTH

One4Life ClickTight All-in-One^BOTH

One4Life Slim ClickTight All-in-One^BOTH

Grow With You ClickTight Plus^BOTH

Grow With You ClickTight^BOTH

Chicco

KeyFit (22 lbs. max)

Fit360^BOTH

OneFit LX All-in-One^BOTH

MyFit

MyFit ClearTex

MyFit Zip

Clek

Liing^BOTH

Fllo^BOTH

Foonf^BOTH

Cybex

Aton G^{BT ONLY}

Aton G Swivel^{BT ONLY}

Callisto G 360^{BT ONLY}

Cloud Q^{BT ONLY}

Sirona S^{BT ONLY}

Evenflo

LiteMax NXT^{BT ONLY}

LiteMax NXT (Revolve180 version)^{BT ONLY}

Shyft DualRide Infant Car Seat Stroller Combo^{BT ONLY}

Shyft DualRide Extra Base^{BT ONLY}

Revolve360 Extend^{BT ONLY}

Revolve360 Extend (meets new side impact standards)^{BT ONLY}

Gold Revolve360 Extend with Green & Gentle Fabric^{BT ONLY}

Revolve360 Slim^{BT ONLY}

Revolve360 Slim (meets new side impact standards)^{BT ONLY}

Gold Revolve360 Slim with Green & Gentle Fabric^{BT ONLY}

Graco

GoMax with Base^BOTH

SnugRide SnugFit 35 DLX^BOTH

SnugRide SnugFit 35 Elite^BOTH

SnugRide SnugFit 35 LX^BOTH

SnugRide SnugFit 35 XT^BOTH

SnugRide 35 DLX ft. Load Leg Technology^BOTH

SnugRide SnugFit 35 XT ft. Load Leg Technology^BOTH

SnugRide SnugLock LX featuring TrueShield^BOTH

4Ever DLX 4-in-1^{FF ONLY}

4Ever DLX Grad 5-in-1^BOTH

4Ever DLX SnugLock 4-in-1^BOTH

Premier 4Ever DLX Extend-2-Fit 4-in-1 featuring Anti-Rebound Bar^{FF ONLY}

EasyTurn 360^BOTH

SlimFit3 LX 3-in-1^{FF ONLY}

TrioGrow SnugLock 3-in-1^BOTH

True3Fit LX 3-in-1 featuring Anti-Rebound Bar^{FF ONLY}

Turn2Me^BOTH (The lockoff on this seat does not hold the seat belt securely when rear-facing, which allows it to hold slack in the lap portion of the seat belt due to the rotation of the carseat. I do not recommend use of the seat belt in RF mode.)

Joie

rue^BOTH

chili spin 360^BOTH

saffron SI^BOTH

Maxi-Cosi

Mico Luxe+

Emme 360^{BT ONLY}

Magellan LiftFit All-in-One

Nuna

PIPA aire rx

PIPA rx

RAVA^{BT ONLY}