Understanding the different parts of a Car Seat

As you prepare to go on family trips, it can be a great time to familiarize yourself with the various car seat parts. Car seat language can confuse even the most informed parents. By understanding the different parts and how they work, this can help your child be as safe and provides guidance on which parts should be used during installation as well as parts that should be checked frequently to ensure they are working safely. Here is a guide to better understand the main parts of a car seat and their individual functions.


Harness straps

These straps come over the shoulders and hips and attach to the buckle located at the crotch strap between the legs. The harness straps should be buckled and secured on every car ride. You will need to adjust them as your child grows. When you place the child into the car seat, you should not be able to pinch more than one inch of fabric on the harness straps. If you pinch the harness straps and you are able to pinch a significant amount of fabric, the harness may be too loose and need adjustment to ensure the child is safely secured in the seat. 

Harness slots

The harness slots are the openings on a car seat that adjust the level of the harness straps closest to the shoulders. When using the seat in the rear-facing position, the harness straps should be at or below your child’s shoulders. When forward-facing, the harness straps should be at or above the shoulders. You may have to look on the back of the seat to see how to move the harness straps to different harness slots. Always look at the car seat manual for guidance and specific instructions for your specific seat. 

Harness adjuster

Harness adjusters allow you to tighten and loosen the harness straps. When preparing your child for a car ride, especially in colder weather, remove any bulky coats or jackets and then tighten the harness straps. The harness adjust may be located underneath fabric or close to the buckle. The harness adjuster helps tighten the straps if they are too loose when you pinch the harness straps. 

Chest clip

The chest clip holds the shoulder straps together over your child’s. In the rear-facing and forward-facing positions this clip should be at armpit level. Internal injury could occur if the clip is placed too low over the soft parts of a child’s body. Always check the position of the chest clip every time you secure the child in the seat. 


Located between a child’s legs on a rear and forward-facing car seats, this buckle secures the harness straps in place. A child should always be buckled into the seat during every time the vehicle is in motion even for feeding or during traffic. 

Lower anchor attachments

These straps attach with clips on each end to the lower anchors found in most vehicle seats. Use them to secure most child safety seats instead of the vehicle’s seat belt. Don’t use them together with a seat belt unless the manufacturer’s instructions specifically state to do so. The lower anchor attachments with have two clips unlike the tether strap that will just have one clip. It is important to know the difference between the lower anchor attachments and tether straps so you do not miss them up when installing the seat. If you are not using the lower anchor attachments, refer back to the car seat manual to see how the straps should be secured to seat to prevent the attachments from hitting the child and causing injuries to the child. 

Tether strap

This single seat-belt-like strap connects the rear of a child safety seat to an anchor point in the vehicle. These straps are typically only used in the forward-facing position to reduce the forward motion of a child’s seat and the child’s body in a crash. Anytime you are using a forward-facing seat, you should use a tether strap. Reference your vehicle’s manual for the exact location of these anchors so you don’t confuse them with cargo hooks. Your manual will show you the specific symbol to look for in your car to know where to attach the tether strap.