babycarseat.infoCar seat reviews & practical buying advice Compare

Diono does not sell this seat on Amazon. See its own site for photos.

Diono Connect3 RXT Backless Booster

A backless booster seat with one mode: backless booster 40 to 120 lb, 38 to 63 in.

At a glance

  • Fits children from 40 to 120 lb
  • Up to 63 in tall
  • Backless booster only
  • 8-year usable life
Not sold on Amazon

Diono lists this seat on its US site. Buy from Diono or an authorized retailer, and confirm the exact model number before you buy.

Diono product page (opens in a new tab) Manual (PDF, opens in a new tab)

Specifications checked against Diono’s US site and manual on . Not hands-on tested. How I research

Who is the Connect3 RXT Backless Booster for?

The Diono Connect3 RXT Backless is a backless belt-positioning booster for children 40 to 120 lb and 38 to 63 in whose ears are below the top of the fully raised vehicle seat or headrest. It attaches with LATCH/UAS connectors, always uses the RED shoulder belt guide strap, and expires eight years from the date of purchase.

Reasons to consider it

  • A seat bottom only, rated for 40 to 120 lb and 38 to 63 in
  • LATCH/UAS connectors, which can keep the booster secured when no child is in it
  • A RED shoulder belt guide strap stored under the seat
  • A cup holder that stores under the seat when not in use

Things to weigh up

  • The child's ears must be below the top of the fully raised vehicle seat or headrest
  • The shoulder belt guide strap must always be used in backless mode
  • Diono's manual does not publish the seat's width or weight
  • Not certified for use in aircraft

My take on the Connect3 RXT Backless Booster

It suits a child whose ears sit below the top of the fully raised vehicle seat or headrest, in a car where that seat or headrest can do the job of a backrest. The trade-off is that everything depends on the vehicle: there is no head support, no recline and no side wings. The Connect3 RXT 2-in-1 shares the same manual and limits, but adds a removable backrest with an adjustable head support and a two-stage recline.

A research summary of Diono’s published specifications and manual, read . Not a hands-on test or a crash-safety rating.

Who the Connect3 RXT Backless Booster fits

This seat covers one stage. Diono gives it a 8-year life from the date of manufacture, so check the date label before using a hand-me-down.

Backless booster40 to 120 lb · 38 to 63 in
Only the base is left, so the vehicle seat has to support the child’s back and head, and the belt guide sits at the hip.
A school-age child with a backpack beside an empty high-back booster

What are the Connect3 RXT Backless Booster weight, height and age limits?

Diono Connect3 RXT Backless Booster limits by mode
ModeChild weightChild heightMinimum ageConditions
Backless booster40 to 120 lb38 to 63 inNot publishedChild's ears must be below the top of the fully raised vehicle seat or headrest

A child must meet every limit for the mode they use. The labels on your seat and its manual are the final word.

Connect3 RXT Backless Booster specifications

Seat weight
Not published
Width
Not published
Usable life
8 years
Aircraft use
Not certified for aircraft

How the Connect3 RXT Backless Booster installs

Lower anchors
LATCH/UAS connectors. Check your vehicle manual for which seating positions have anchors, and switch to the seat belt once the child passes the anchor weight limit in the manual.

Every install is a fit between one seat and one vehicle. Read both manuals, and use a free inspection station if anything is unclear.

An empty car seat installed on a back seat, seen through an open car door

Will it fit your car?

Diono does not publish a width for this seat, so measure your back seat and compare it with the seat in a store before buying.

  • Check your vehicle manual for lower anchor positions and any head-restraint rules.
  • Rear-facing seats need front-seat room: try the install behind the driver before you commit.
  • Not certified for aircraft use: plan on gate-checking it or using a different seat to fly.

What features does the Connect3 RXT Backless Booster have?

  • LATCH/UAS connectors

What to know before you live with it

How it installs

The child is held only by the vehicle's lap and shoulder belt; a lap belt alone is not allowed. The booster's LATCH/UAS connectors clip to the lower anchors after you press the cam lock lever and extend the straps, then you tighten one strap and then the other while pushing the booster back. For the backless booster, the manual says to push it all the way back so it touches the vehicle seat back, with the whole seat bottom flat on the vehicle seat. It will still move a little against the vehicle seat even when tight. Do not use LATCH/UAS if it interferes with the seat belt.

Source: Diono Connect3 RXT Backless Booster manual (PDF)

The shoulder belt guide strap

This is the one part to get right every ride. The manual's warning says that in backless mode the seat must be used with the shoulder belt guide strap. You take the strap out of the storage area under the seat and feed it between the backrest mounting bar and the seat base. After the child is buckled, attach the RED guide to the shoulder belt and adjust its length so the guide sits just above the shoulder. The lap belt goes through both lap belt guides, low across the hips, and the shoulder belt must not touch the neck.

Source: Diono Connect3 RXT Backless Booster manual (PDF)

Checking the vehicle seat

A backless booster has no head support of its own, so the manual allows it only for children whose ears are below the top of the fully raised vehicle seat or headrest. Avoid seats with motorized, dual retractor, inflatable or door-mounted belts. Never use it on a rear-facing or side-facing vehicle seat or on a folded seat back. The shoulder belt must pass under the lap belt guide, never over the armrest, and if the buckle gets pulled across the lap belt guide into the seat, the manual says to choose another seating position.

Source: Diono Connect3 RXT Backless Booster manual (PDF)

Is the Connect3 RXT Backless Booster recalled?

No campaign in the current NHTSA child-restraint data names this model family, and I have not run a separate review for it. Check your seat’s model number and date of manufacture before use.

NHTSA recall search · Recent car seat recalls

Connect3 RXT Backless Booster: common questions

What are the Connect3 RXT Backless limits?

The manual says 40 to 120 lb (18 to 54 kg) and 38 to 63 in (97 to 160 cm). The child's ears must also be below the top of the fully raised vehicle seat or headrest.

Diono Connect3 RXT Backless Booster manual (PDF) (opens in a new tab)

How do I wash the Connect3 RXT Backless cover?

Pull the elastic loops off the tabs around the shell, remove the seat cushion and do not wash the foam. Machine wash the cover separately in cold water on a gentle cycle with mild detergent, or hand wash, and dry it flat away from direct sunlight.

Diono Connect3 RXT Backless Booster manual (PDF) (opens in a new tab)

When does the Connect3 RXT Backless expire?

The manual says it is expired over eight years from the date of purchase. Do not use it after that, or if any part is damaged, missing or broken.

Diono Connect3 RXT Backless Booster manual (PDF) (opens in a new tab)

Can I take the Connect3 RXT Backless on a plane?

Not for use on the aircraft seat. Diono states it is not certified for use in aircraft because aircraft seats lack the shoulder belt it needs.

Diono Connect3 RXT Backless Booster manual (PDF) (opens in a new tab)

Can I add a backrest to the Connect3 RXT Backless?

The manual says not to use this restraint with any other backrest or cushions. The backrest and head support are part of the separate Connect3 RXT 2-in-1.

Diono Connect3 RXT Backless Booster manual (PDF) (opens in a new tab)

Answers refer to the model and manual version on this page. Check the instructions supplied with your seat.

Before you buy

  1. Weigh and measure your child. The limits above are the manufacturer’s, and a child has to meet all of them for the mode they will use.
  2. Confirm the exact version. Colors, retail exclusives and model numbers change limits more often than you would expect.
  3. Read the manual before you buy, not after. It is linked above and holds the fit rules, the install methods and the expiry.
  4. Check recalls by model number and date of manufacture, and register the seat with Diono so you hear about the next one.

Sources

Other Diono booster seats

ModelTop child weightSeat weightWidthUsable life
Connect3 RXT Backless Booster (this seat)120 lb——8 years
Connect3 R 2-in-1 High-Back Booster120 lb——8 years
Connect3 R Backless Booster120 lb——8 years
Connect3 RXT 2-in-1 High-Back Booster120 lb——8 years
Cambria 2 2-in-1 High-Back Booster120 lb——8 years
Cambria 2XT 2-in-1 High-Back Booster120 lb——8 years
Everett NXT High-Back Booster120 lb——8 years
Monterey 2XT 2-in-1 High-Back Booster120 lb——8 years
Monterey 4DXT 2-in-1 High-Back Booster120 lb——8 years
Monterey 5iST FixSafe High-Back Booster120 lb——8 years
Monterey 6XT SafePlus High-Back Booster120 lb——8 years
Monterey 6DXT SafePlus High-Back Booster120 lb——8 years
Solana Backless Booster120 lb——8 years
Solana 2 Backless Booster120 lb——8 years

Other backless booster seats whose published weight and height limits overlap the Connect3 RXT Backless Booster.