Peg Viaggio Flex 120 Review

A search for “narrow booster seat” can leave you with disappointingly few results. But if that’s how you landed here, you’ve come to the right place! Let’s talk about the tried-and-true slim booster seat, the Peg Viaggio Flex 120.

The Peg Flex 120 has become a go-to for tight three-across setups for good reason. It measures just 14 inches across the seat bottom and 17 inches at its widest point in the narrowest mode, works with non-removable vehicle headrests, and has height and weight limits that are unusually high for a high-back booster. It even folds, which opens up some interesting possibilities for travel.

Consider the Peg Flex 120 if:

• You need three across
• Your vehicle has non-removable headrests
• You need a high-back booster with high limits
• You need a high-back booster for travel

Keep looking if:

• ^You need a lightweight booster
• You’re on a tight budget

I’m Carly, a CPST and mom of three, and the Peg Viaggio Flex 120 has been a game-changer in my own personal (or should I say, my husband’s) three-across scenario.

Peg Viaggio Flex 120 Height and Weight Limits

• Weight range: 40–120 pounds
• Height range: 39–63 inches
• Minimum age: At least 4 years old, though we strongly recommend 5+ when possible
• Booster type: High-back only
• Seat weight: About 14 pounds
• Expiration: 12 years

The 120-pound and 63-inch maximums are among the highest available, and limits that high are especially rare in a high-back booster. The 39-inch minimum height is also notable because many boosters have a 43-inch minimum.

Of course, meeting the numbers doesn’t automatically mean a child is ready for a booster. They also need to be mature enough to sit correctly for the entire ride without a harness helping them stay in position.
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Are Booster Seats Easier for Three-Across Car Seat Setups?

There’s a common misconception that switching to a booster will make a three-across setup easier. Unfortunately, that’s generally not true for one simple reason: your child needs to be able to buckle the seat belt every single ride.

With a harnessed car seat, you only have to access the vehicle seat belt once during installation. In a tight three-across setup, a harnessed seat with a lock-off, like the Graco SlimFit3 LX, can also usually tolerate a slightly off-center installation. A booster needs to stay properly positioned for the seat belt to fit correctly, and there needs to be enough room between the seats for your child to reach the buckle every time.

There’s also the issue of unbuckling. In a very tight setup, reaching for the booster buckle can create a risk of accidentally unbuckling the adjacent car seat.

Tech Tip: For these reasons, it’s often recommended to keep an otherwise booster-ready child in a harness for as long as possible when you’re working with a super-tight three-across setup.

When Is a Child Ready for a Booster Seat?

Eventually, all harnessed seats are outgrown and a booster becomes a must. Or maybe you’re replacing one, two, or even three seats to make an upcoming three-across setup work, and moving a booster-ready child into a booster makes the most sense for your family.

For the Peg Viaggio Flex 120, a child needs to:

• Be at least 4 years old (though we strongly recommend 5+ when possible)
• Weigh at least 40 pounds
• Be at least 39 inches tall
• Be mature enough to sit correctly for the entire ride without a harness helping them stay in position

If your child checks all of those boxes, a booster may also be the more cost-effective purchase rather than buying another harnessed seat they’ll eventually outgrow.

Why the Peg Viaggio Flex 120 Works for Three Across

The Peg Flex 120 has an impressive résumé when it comes to three-across eligibility. It’s not just that the booster is narrow. Several of its features can make a big difference when you’re trying to solve an especially tight back seat.

• It’s just 14 inches wide at the seat bottom. At its widest point, the Peg Flex 120 measures 17 inches in its narrowest mode. Most other boosters are 17+ inches wide.
• There are no armrests. This leaves more space for actually reaching and buckling the seat belt, which is one of the biggest challenges with boosters in three-across setups.
• It works with non-removable headrests. The Peg Flex 120 is one of the very few high-back boosters that works with non-removable vehicle headrests, giving you more flexibility in which seating position you can use.
• The recline is adjustable. This can help the booster fit better alongside the contours of an adjacent car seat.

That last point about vehicle headrests can be a surprisingly big component of the three-across puzzle. A narrow booster isn’t very helpful if it isn’t compatible with the vehicle seat where you actually need to put it!

A Quick Note About Rigid LATCH and Three Across

The Peg Flex 120 also has rigid LATCH, but this is one feature you often won’t be able to use in a three-across setup. The booster may need to sit slightly off-center from the vehicle’s lower anchors to make everything fit.

We’ll talk more about the benefits of rigid LATCH below, but don’t assume you’ll be able to take advantage of it just because the booster has it.

A New Booster Is Cheaper Than a New Car

I know, I know, a $300 booster seat was probably not on your bingo card when you set out to solve your three-across puzzle. But it’s way less expensive than a new vehicle!

There are other narrow booster seats to consider, but they come with their own tradeoffs. The Maxi-Cosi Tanza is a newer, slightly lower-priced option, but a major downside is its shallow seat pan, which may cause kids to slouch due to a lack of thigh support. The Axkid Up has many of the same great features as the Peg Flex 120, and more, but comes with a higher price tag.

For families who specifically need the Peg Flex 120’s combination of a narrow profile, high limits, non-removable headrest compatibility, and adjustability, that $300 price tag may be easier to swallow when the alternative is changing your entire vehicle setup.

The “Flex” in the Peg Viaggio Flex 120: An Adjustable Fit

The Peg Flex 120 is highly adjustable, which can help you get a more customized fit for both your child and your vehicle.

Adjustable Headrest, Backrest and Side Wings

The backrest and headrest adjust separately in height, rather than moving together. The side wings are adjustable, too, and unlike other boosters with expandable sides, they don’t automatically widen as you raise the height. You can adjust them separately based on the fit you need.

Recline for Comfort and Vehicle Fit

The Peg Flex 120 also reclines, which can provide additional comfort for your child and help the booster fit better with your vehicle seat and adjacent car seats.

Works With Non-Removable Vehicle Headrests

And in case you missed it the first few times I mentioned it, the Peg Flex 120 works with non-removable headrests!

Even if you don’t need its slim profile for three across, this is a big reason to consider the Peg Flex 120.

How Rigid LATCH Works on the Peg Viaggio Flex 120

The Peg Flex 120 is one of the few boosters with rigid LATCH. Unlike with a harnessed car seat, LATCH on a booster isn’t what holds your child in place. One of its main purposes is to prevent the booster from becoming a projectile when no one is sitting in it. If a booster doesn’t have lower anchor connectors, or they can’t be used in that seating position, the booster needs to be buckled when unoccupied.

Rigid LATCH also keeps the booster centered on the vehicle seat as your child climbs in, gets out, and buckles themselves. This can help with correct seat belt fit, especially for kids who are buckling independently and may not notice that their booster has shifted.

Why Rigid LATCH Is So Convenient

Because the connectors are rigid rather than attached to flexible straps, attaching the Peg Flex 120 to the vehicle is even faster than using the flexible lower anchors found on some other boosters. Just remember what we talked about above: you may not be able to use rigid LATCH in a three-across setup if the booster needs to sit slightly off-center from your vehicle’s lower anchors.

The Peg Viaggio Flex 120 Folds for Travel

One of the Peg Flex 120’s more unique features is that it folds! This makes it an interesting option if you need a high-back booster for travel.

High-back boosters are probably the trickiest category of car seat to fly with because they can’t be used in the airplane seat. The Peg Flex 120 folds compactly enough to be stored in an overhead bin, which means you don’t have to check it and risk having it lost or damaged along the way. There’s also an accessory travel bag available that can make carrying it even easier.

Is the Peg Flex 120 Easy to Travel With?

I haven’t personally traveled with this seat, so I can’t speak to what it’s like to take through an airport. And at 14 pounds, it’s definitely not what I’d consider a lightweight booster.

But I do find the folding feature helpful when loading the seat into a car, especially when it’s going into the third row. Being able to fold a high-back booster down into a more compact package can make maneuvering it into place much easier.

Peg Viaggio Flex 120: What to Know Before Buying

No seat is without its downsides, and most of the Peg Flex 120’s are actually related to its otherwise helpful features. Here’s what I’d keep in mind before deciding if it’s right for your setup.

You May Not Be Able to Use Rigid LATCH in Three Across

As helpful as rigid LATCH can be, it often can’t be used in a three-across combination. The booster may need to sit slightly off-center from the vehicle’s lower anchors to make your setup work, which means you won’t be able to connect the rigid LATCH.

Watch the Lap Belt Position

The Peg Flex 120’s lack of armrests creates valuable space for buckling, but there is a tradeoff. Without armrests, the lap belt can creep up toward the belly when it needs to stay positioned on the pelvis instead.

I’ve found this to be more of a problem in center seating positions, where the two sides of the lap belt are generally anchored closer together. It can also be more prominent when the booster’s recline feature is being used.

Tech Tip: Always check the seat belt fit after your child buckles. The lap belt needs to stay positioned on the pelvis rather than riding up onto the belly.

It’s High-Back Only

The Peg Flex 120 does not convert into a backless booster. If you decide to switch your child to backless mode before they’ve completely graduated from needing a booster, you’ll need to purchase another booster.

It’s Not a Lightweight Booster

At 14 pounds, the Peg Flex 120 is heavy for a booster seat. The folding feature can make it easier to maneuver, but the weight is worth considering if you’re looking for something you’ll frequently move between vehicles.

Is the Peg Viaggio Flex 120 Worth It?

When it comes down to it, the Peg Perego Viaggio Flex 120 is a fairly niche booster, but for the family who needs what it offers, it very well may prevent you from needing a new vehicle.

Its narrow profile, lack of armrests, compatibility with non-removable headrests, high height and weight limits, and adjustable design give it an impressive résumé for complicated three-across setups. It’s not inexpensive or lightweight, and there are some important belt-fit and rigid LATCH considerations to keep in mind, but it solves problems that relatively few high-back boosters can.

If you’re trying to make an especially tight three-across setup work, we highly recommend working with a CPST. There are a lot of complexities that can go unnoticed, and crowd-sourced solutions may not be accurate.

Peg Viaggio Flex 120 FAQs

What Are the Peg Viaggio Flex 120 Height and Weight Limits?

The Peg Perego Viaggio Flex 120 can be used for children from 40–120 pounds and 39–63 inches tall. We recommend waiting until at least age 5 when possible and making sure your child is mature enough to sit correctly for the entire ride.

Is the Peg Viaggio Flex 120 Good for Three Across?

Yes, three across is where the Peg Flex 120 really shines. It measures just 14 inches across the seat bottom and 17 inches at its widest point in the narrowest mode, and the lack of armrests leaves valuable space for buckling.

Does the Peg Viaggio Flex 120 Work With Non-Removable Headrests?

Yes! This is one of the Peg Flex 120’s standout features. It’s one of the few high-back boosters that works with non-removable vehicle headrests, which can give you more flexibility when figuring out where each seat needs to go.

Does the Peg Viaggio Flex 120 Have LATCH?

Yes. The Peg Flex 120 has rigid LATCH, which keeps the booster attached to and centered on the vehicle seat when your child gets in and out. Just keep in mind that you may not be able to use rigid LATCH in a tight three-across setup if the booster needs to sit slightly off-center.

Does the Peg Viaggio Flex 120 Convert to a Backless Booster?

No. The Peg Flex 120 is high-back only. If your child switches to a backless booster before they’re ready to ride without a booster altogether, you’ll need to purchase a separate one.

Is the Peg Viaggio Flex 120 Good for Travel?

The folding design makes it an interesting high-back booster for travel because it can be stored in an airplane overhead bin. It does weigh 14 pounds, though, and I haven’t personally traveled with it, so I wouldn’t consider it a lightweight travel booster.

Does the Peg Viaggio Flex 120 Fold?

Yes! The Peg Flex 120 folds into a more compact size, which can make it easier to store, travel with, or maneuver into a third row.

Is the Peg Viaggio Flex 120 Worth It?

If you need a narrow high-back booster for a complicated three-across setup, the Peg Flex 120 offers a combination of features that can be hard to find elsewhere. At around $300, it’s certainly an investment, but as I said earlier: it may be a whole lot cheaper than needing a new car!
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