Labels on car seats provide critical safety information that is specific to your car seat. The labels are required by federal guidelines. There will be a sticker that states the seat has been crash tested in accordance with the Federal Motor Vehicle Safety Standards (FMVSS213).
Child safety seat labels will provide the weight and height limits of the seat and any limitations that may need to be considered. It is always important to locate this information to be sure the car seat is appropriate for your child. Additional items you will find on labels include: the date of manufacture and expiration, the manufacturer’s name, the child safety seat's model number, the belt path (especially important for a convertible seat), an airplane symbol (indicating the seat meets airline requirements for flying), and helpful images for installation.
For rear-facing child safety seats (and convertibles), there will be a label that helps guide you to make sure the seat is reclined correctly. This will look different depending on which seat you have but might be a line to level the seat with the ground, a ball that has to be in a certain colored slot, or another visual to help you install the seat in the appropriate reclined position. There will also be an air bag warning reminding you to never place a rear-facing seat in front of an active airbag.
Car seat labels are a critical safety feature that helps guide you to make sure your seat is as safe as possible. We do not recommend that you use a used or second-hand seat because the labels may be missing, and you do not know if the seat has been in a motor vehicle crash. While it may be tempting to remove your stickers from your car seat, make sure you leave all the stickers on the seat to ensure all safety features are followed correctly by all dcaregivers.
https://www.consumerreports.org/car-seats/how-to-know-if-child-car-seat-meets-us-standards/