Britax KIDFIX III M Review – European Booster Seat

(Last Updated On: June 14, 2019)
Britax KIDFIX III M

Britax KIDFIX III M

Britax’s range of European booster seats has grown yet again! The new KIDFIX III M looks at first glance to be nearly identical to previous models, but it has a few surprises up its sleeve. Let’s take a closer look, and see how it compares to the KIDFIX II XP SICT that we’ve reviewed previously.

CSFTL Quick Stats

  • High back booster weight range: 15 to 36 kg (33 to 80 pounds)
  • Lowest belt guide position: 38 cm (15 inches)
  • Highest belt guide position: 56 cm (22 inches)

Measurements

  • Width at widest point on base (at the front): 43 cm (17 inches)
  • Width at narrowest point on base (at the rear): 38 cm (15 inches)
  • Width at widest point of seat: 55.5 cm (22 inches) with SICT stored; 58.5 cm (23 inches) with one SICT extended
  • Seating area width (at the back): 30 cm (12 inches)
  • Seat pan depth: 35 cm (14 inches)

Unique Features

  • ISOFIT
  • SecureGuard clip to keep the lap belt low over the pelvis
  • Extendable side impact protection
  • Good safety ratings on ADAC testing

Name Changes

The KIDFIX III M follows Britax’s new, sleeker naming scheme. Instead of appending multiple abbreviations – like XP and SICT – onto the end of the seat name, only one letter is used to designate where a seat falls in the lineup. Newer seats from Britax in the EU will all follow this naming scheme.

Features

No XP Pad

XP Pad on the Kidfix II XP SICT

The most noticeable difference between the KIDFIX II XP SICT and the KIDFIX III M is that the III M does not feature an XP Pad. The pad often caused belt retraction issues, so it’s not surprising it has gone away for now. Britax has assured us that the KIDFIX III M performs quite well in testing without the pad.

SecureGuard

Britax KIDFIX III M SecureGuard clip

Britax KIDFIX III M SecureGuard clip

Like its predecessor, the KIDFIX III M features the SecureGuard clip. Acting as a fourth point of contact for the vehicle seat belt, the SecureGuard clip helps keep the lap belt low on the pelvis.

I find it easier to slide the lap belt into the SecureGuard clip before buckling the seat belt, but my son finds it easier to buckle and then tuck the lap belt into the clip when he buckles himself.

Side Impact Protection

Britax KIDFIX III M SICT fully extended

Britax KIDFIX III M SICT fully extended

The KIDFIX III M features side impact protection that is identical to that on the KIDFIX II XP SICT. It unscrews from the side of the seat closest to the vehicle door to absorb crash forces during a side impact.

ISOFIT

Britax KIDFIX III M Isofit arms

Britax KIDFIX III M Isofit arms

The KIDFIX III M features ISOFIT connectors just like the KIDFIX II XP SICT. The only difference is that the handle to adjust the ISOFIT isn’t quite as obvious because there is no plastic panel at the front of the seat to show where the handle is located. But never fear, it’s still there!

The main benefit of ISOFIT is that it isn’t necessary to remember to buckle the booster seat when it isn’t occupied. ISOFIT can also provide some stability to the seat when the child climbs in and out. It isn’t required for use but when it’s not used, the booster seat needs to be buckled at all times to prevent it from becoming a projectile during a crash.

Longer Seat Pan = More Thigh Support

Britax KIDFIX II XP SICT vs Britax KIDFIX III M

Britax KIDFIX II XP SICT vs Britax KIDFIX III M

One major difference between the KIDFIX II XP SICT and the KIDFIX III M is that the seat pan on the III M is significantly longer. A common complaint about the II has been that the seat pan is very short, leaving bigger kids with uncomfortably dangling legs. With about 4 cm of additional thigh support, the III M provides much more support that should keep kids comfortable longer. My son, who is on the smaller side, noted that his legs were more comfortable in the III M.

Better Seat Belt Retraction

Another common complaint about the KIDFIX boosters has been that vehicle seat belt retraction is sometimes poor when the booster headrest is on a lower setting, below the car seat shell. The KIDFIX III M has better belt retraction than previous versions, which is great news!

Installation With ISOFIT

Britax KIDFIX III M Isofit handle

Britax KIDFIX III M Isofit handle

First, extend the ISOFIT arms by squeezing the handle at the bottom front of the seat and pulling the arms out the back. Extend them fully, then line them up with the ISOFIX anchors in the vehicle. In some vehicles, the ISOFIX anchors are too deep in the vehicle seat to be easily accessible. If this is the case, the included ISOFIX guides make it easier to access the anchors.

Britax KIDFIX III M Isofit indicator

Britax KIDFIX III M Isofit indicator

Now, push the ISOFIT arms onto the ISOFIX anchors. You’ll hear and feel a click, and both indicators will turn green.

Britax KIDFIX III M Isofit handle

Britax KIDFIX III M Isofit handle

Squeeze the handle at the front of the seat again and push the entire seat back so the back sits flush against the vehicle seat. The back of the booster is articulated so it can adjust to the angle of the vehicle seat.

Installation Without ISOFIT

Simply place the booster flush on the vehicle seat, thread the vehicle seat belt through the shoulder belt guide, extend the SICT, then buckle.  Remember to buckle the booster seat in when it’s not in use to prevent the booster seat from becoming a projectile during a crash.

Headrest Adjustment

Britax KIDFIX III M headrest adjuster

Britax KIDFIX III M headrest adjuster

The headrest can be adjusted up or down to fit the child. Squeeze the handle at the back of the headrest, then slide it up or down.

The manual states that the bottom of the headrest should be approximately two fingers’ width above the top of the child’s shoulders. It’s fine to adjust the height of the headrest without removing the seat from the vehicle, though I find it easier to slide the seat forward before attempting to do so.

Setting Up Side Impact Protection

Britax KIDFIX III M deploying the SICT

Britax KIDFIX III M deploying the side impact protection

The side impact protection should only be used on the side of the booster that is next to the vehicle door. Unscrew the side impact protection until it is 5 mm from the door or it’s fully unscrewed.

Fit to Child

6 Years Old

Britax KIDFIX III M 6 year old fit

Britax KIDFIX III M 6 year old fit

This model is 6 years old, weighs 18 kg, and is 112 cm tall. He previously rode in the KIDFIX II XP SICT, but after a minor crash, that seat has been replaced with the KIDFIX III M. He gets a great fit in the booster, with the lap belt low over his pelvis and the shoulder belt centred over his collarbone.

One of the first things he noted when he first tried this booster was that it didn’t have an XP Pad. He was worried that it was less safe, but also very happy to not have the pad, because he found it a bit annoying. After being reassured he was still very safe, he has loved his new booster seat! And, as always, he’s a big fan of having a blue seat.

He’s able to buckle and unbuckle himself, though in our BMW i3 he sometimes has trouble if the booster has shifted towards the buckle. In that case, he climbs back out and we pull the booster over slightly so he can buckle and unbuckle with ease again.

Important Information: Where to Find

Expiration: Britax doesn’t specify a maximum period of use.

Britax KIDFIX III M manual storage

Britax KIDFIX III M manual storage

Manual Storage: A hinged door on the back of the seat conceals a storage compartment designed to hold the manual. In fact, there are 28 separate manuals in there, each in a different language!

Airplane Approval: Like all booster seats, the Kidfix II XP SICT is not approved for airplane use. In addition, it’s a relatively heavy seat and does not disassemble, so it wouldn’t be a great choice for travel.

Overall Thoughts

The KIDFIX III M is a great addition to the Britax booster lineup. It’s easy to use, robust, and fixes many of the niggling issues that some users experienced with previous versions. With the addition of a longer seat pan it will keep kids comfortable even longer, and its versatility means it can fit in most vehicles.