Clek Infant-thingy Review: Clek for Noobs!


infant thingy green

2018 Clek Infant-thingy Infant Insert

The Clek Foonf and Fllo convertible carseats both have minimum starting weight limits of 14 lbs. with the addition that the child must be able to sit upright alone. Right off the bat, this eliminates both seats from parents who want to use a convertible from birth since most babies don’t reach this “advanced” stage until 6+ months of age. Enter the Infant-thingy, Clek’s new hotly anticipated insert that allows the Foonf and Fllo to fit noobs from 5 lbs. It’s available in Shadow black Crypton fabric, so it’s easily cleanable for those baby blow-outs you’ll inevitably have.

  • Rated from 5-22 lbs., 19-33” rear-facing use only
  • Body support cushion is required until 11 lbs.
  • Crotch strap adjusted to the rear slot position
  • Energy-absorbing material in head support
  • Infant-thingy manual supersedes Foonf and Fllo manuals
  • Bottom harness slot with body support: 9”
  • Crotch strap position: 3”

Before using the Infant-thingy, the carseat’s headrest must be removed. Raise the headrest to its uppermost position, then use the troubleshooting tool on the back of the carseat to release it. There’s a small hole on the front of the right headrest guide where the tool fits in (that’s the one that doesn’t have the push button release). If you’ve lost the tool, you can use a paperclip. Don’t worry, there are directions for this maneuver in the Infant-thingy instruction manual. Be sure not to lose the headrest because you’ll definitely need it later on when your child is taller.

Clek troubleshooting tool with circle removing Clek headrest

Head Support

The Infant-thingy’s head support must be used until the child weighs 14 lbs. and is 25” tall, and is able to sit upright alone. After the Infant-thingy’s head support is removed, the carseat’s headrest must be placed back on the carseat because your child must have that vital head protection.

Wait, what? Use a head support; one or the other, but not both. In print, it seems complicated, but use your common sense. When your baby is small, use the Infant-thingy—that’s why you bought it, after all. When your baby gets too tall for the Infant-thingy head support, switch to the carseat’s headrest. You want your child’s head fully encased in head protection goodness. Your baby is too tall for the Infant-thingy head support when his head is at or above the top of the head support.

Infant Thingy in Fllo Infant Thingy in Fllo with headrest

Body Support

The body support is required for use between 5 and 11 lbs. but can be used until a child weighs 22 lbs. It must also be used when the carseat headrest is on and the child is less than 14 lbs., under 25” tall, and unable to sit unassisted.

You’ll notice when you get the Infant-thingy that the back of the body support is thicker than the back of the head support. That’s to help keep your child’s airway open by helping his head stay back—pretty cool, huh?

When using the body support, the inner crotch strap position is required, though if needed, the longer crotch strap length can be used. If you have a 2013 or older Foonf, you can order the dual-length crotch strap from Clek. And don’t forget to use the belly pad with the buckle—it’s required.

There are hip supports that are positioned between the lap straps and the child’s hips. If you try to route the lap straps under the hip supports, the harness will twist; these support pads are supposed to be between the harness and the child. It’s different than what we’ve all heard before about padding between the baby and the harness and it’s A-OK because it’s from the manufacturer.

Infant Thingy shorter crotch strap Infant Thingy longer crotch strap Infant Thingy hip pad

Harness Slots and the Infant-thingy

The goal of the Infant-thingy is to get a newborn to fit the minimum requirements of the Foonf and Fllo: proper fit is defined as a minimum of 14 lbs., 25” minimum height, and a child being able to sit upright alone. Out of the box, the 2014 Foonf and the original Fllo both have 10” bottom harness slots out. Those are particularly high when we’re talking about fitting a 5 lbs. newborn into a seat. In fact, they may still be high even with the Infant-thingy installed. Remember our rule for rear-facing carseats? The harness slots must be at or below the shoulders. Clek has a different rule for us with the Infant-thingy, though, and that’s OK because they’ve done the testing. It is acceptable if the harness comes out above the child’s shoulders when it is routed through the bottom slots. This is because the Infant-thingy’s manual supersedes the Foonf and Fllo manuals and the manual says it’s OK for the harness to come out above in this instance. Once your baby grows taller, you’ll want the harness slots that you use to be at or below the shoulders.

Initially, you’ll install the head support in the 3rd slots above the bottom slots. As your child gets taller and you move the harness slots up, you’ll also move the head support up so that it’s always 3 slots above the harness slots being used.

Inserting Infant Thingy head support

You may have noticed on your carseat that you have 6 sets of slots in the shell instead of 5. Good catch! Just ignore that extra lower set because you won’t use them and Clek certainly doesn’t want you cutting slots in your cover. If you’d like to use those extra set of slots, you can purchase a 6 slot carseat jacket directly from Clek; give them a ring at 866-656-2462.


The Clek Infant-thingy provides excellent fit for a small baby into a Foonf or Fllo. It’s a great addition to the Clek lineup that makes their convertibles even more versatile, especially for parents who don’t want to start with a rear-facing only infant seat from the newborn stage. Made from favorite comfy Crypton fabric means clean up will be a breeze for inevitable baby messes and the black fabric coordinates with their entire fashion line. The Infant-thingy is available for MSRP $69.99 from or


Thank you to Clek for providing us with our Infant-thingy for review. No other compensation was provided and the opinions are entirely those of CarseatBlog.