1 / 8 Product image 1
Amazon product images. See this listing on Amazon
CERTAIN CONTENT THAT APPEARS ON THIS SITE COMES FROM AMAZON. THIS CONTENT IS PROVIDED ‘AS IS’ AND IS SUBJECT TO CHANGE OR REMOVAL AT ANY TIME.
Price on Amazon.com as of 2026-11-02 21:52 UTC, and subject to change.
An all-in-one car seat with 3 modes: rear-facing harness 5 to 40 lb, 19 to 40 in; forward-facing harness 30 to 65 lb, 34.4 to 49 in; belt-positioning booster (high-back) 40 to 100 lb, 43.4 to 52 in.
Opens Amazon.com in a new tab. As an Amazon Associate I earn from qualifying purchases.
CERTAIN CONTENT THAT APPEARS ON THIS SITE COMES FROM AMAZON. THIS CONTENT IS PROVIDED ‘AS IS’ AND IS SUBJECT TO CHANGE OR REMOVAL AT ANY TIME.
The Maxi-Cosi Petra is a 3-mode all-in-one seat: rear-facing harness for 5 to 40 lb and 19 to 40 in., forward-facing harness for 30 to 65 lb and 34.4 to 49 in., and high-back booster for 40 to 100 lb and 43.4 to 52 in. The manual says not to use it more than 10 years after manufacture.
The Petra suits a family that wants the same limits as the Pria in a lighter seat, with lower anchors allowed to a higher child weight. Maxi-Cosi lists it at 14.75 lb, and its manual allows lower anchors up to 55 lb, where the Pria manual stops at 50 lb. The trade-off is fewer conveniences: its product page does not list a magnetic chest clip, and there is no backless mode.
A research summary of Maxi-Cosi’s published specifications and manual, read . Not a hands-on test or a crash-safety rating.
This seat covers 3 stages, and a child has to meet every limit of the stage they are in. Maxi-Cosi gives it a 10-year life from the date of manufacture, so check the date label before using a hand-me-down.
| Mode | Child weight | Child height | Minimum age | Conditions |
|---|---|---|---|---|
| Rear-facing harness | 5 to 40 lb | 19 to 40 in | Not published | — |
| Forward-facing harness | 30 to 65 lb | 34.4 to 49 in | Not published | — |
| Belt-positioning booster (high-back) | 40 to 100 lb | 43.4 to 52 in | Not published | — |
A child must meet every limit for the mode they use. The labels on your seat and its manual are the final word.
Every install is a fit between one seat and one vehicle. Read both manuals, and use a free inspection station if anything is unclear.
Maxi-Cosi does not publish a width for this seat, so measure your back seat and compare it with the seat in a store before buying. It weighs 14.75 lb, which matters if you will move it between cars or carry it through an airport.
Sea Shadow.
You use either the vehicle belt or the lower anchor belt, never both. Rear-facing, the base must sit flat on the vehicle seat, the tether stays stored, and the seat must touch the seat in front or be as close as possible. Forward-facing, the seat goes upright in Position 1 and the tether must always be used when anchors are available. The lower anchors are allowed for a child up to 55 lb; above that, the vehicle belt is required, up to 65 lb. The seat should not move more than 1 in. at the belt path.
The Petra has 3 positions. Rear-facing, Position 3 is reclined and Position 2 semi-reclined; Position 1 is never used rear-facing. For a child who cannot sit up unassisted, the rear-facing level line must be parallel with the ground in Position 2 or 3. A child who can sit up unassisted may ride more upright in Position 2. If needed, the manual allows tightly rolled towels or foam pool noodles under the front of the seat. Forward-facing and booster modes use Position 1, fully upright.
You do not need to remove the harness system to take the pad off, but the manual says never to pull the harness strap fully out of the seat, because it cannot be rethreaded. You loosen the straps, raise the headrest to its highest position, undo the fabric tab fasteners and work the pads off, unbuckling the harness to pull the seat pad over the buckle. Machine wash separately in cold water on a gentle cycle, with no bleach, and tumble dry separately for 10 to 12 minutes on low heat.
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.
The manual says not to use the lower anchors for a child weighing more than 55 lb. Above that, install the seat with the vehicle belt and tether for a child up to 65 lb.
Maxi-Cosi Petra All-in-One user guide (PDF) (opens in a new tab)
Maxi-Cosi's product page says it is proudly made in Columbus, Indiana. The same page lists machine washable, dryer safe fabrics and 2 removable, dishwasher safe cup holders.
Maxi-Cosi's product page lists an 8-position QuikFit headrest and harness that adjusts with one hand, plus a 3-position adjustable base.
The manual says it is certified for aircraft use with the internal harness. Use it only on forward-facing aircraft seats, and store the lower anchor belt and tether when installing with aircraft belts.
Maxi-Cosi Petra All-in-One user guide (PDF) (opens in a new tab)
Both have the same three modes and limits. The Pria manual stops lower anchor use at 50 lb, compared with 55 lb in the Petra manual.
Maxi-Cosi Pria, Pria Max and Pria Max+ user guide (PDF) (opens in a new tab)
Answers refer to the model and manual version on this page. Check the instructions supplied with your seat.
| Model | Top child weight | Seat weight | Width | Usable life |
|---|---|---|---|---|
| Petra All-in-One Convertible Car Seat (this seat) | 100 lb | 14.75 lb | — | 10 years |
| Sela All-in-One Convertible Car Seat | 100 lb | 27.25 lb | — | 10 years |
| Kani 4-in-1 Convertible Car Seat | 100 lb | 23.2 lb | — | 10 years |
| Pria Max+ All-in-One Convertible Car Seat | 100 lb | 16.5 lb | — | 10 years |
| Pria Max All-in-One Convertible Car Seat | 100 lb | 16.8 lb | — | 10 years |
| Pria All-in-One Convertible Car Seat | 100 lb | 16.5 lb | — | 10 years |
| Romi 2-in-1 Convertible Car Seat | 50 lb | 9.2 lb | — | 10 years |
Other all-in-one seats whose published weight and height limits overlap the Petra All-in-One Convertible Car Seat.
| Mode | Weight | Height |
|---|---|---|
| Rear-facing harness | 5–40 lb | 19–40 in |
| Forward-facing harness | 30–65 lb | 34.4–49 in |
| Belt-positioning booster (high-back) | 40–100 lb | 43.4–52 in |
| Backless booster | 40–100 lb | 43.4–57 in |
$379.99Caspian Caviar · Amazon price as of 2026-11-02 21:52 UTC, subject to change
| Mode | Weight | Height |
|---|---|---|
| Rear-facing harness | 5–40 lb | 19–40 in |
| Forward-facing harness | 30–65 lb | 34.4–49 in |
| Belt-positioning booster (high-back) | 40–100 lb | 43.4–52 in |
$269.99Sea Shadow · Amazon price as of 2026-11-02 21:52 UTC, subject to change
| Mode | Weight | Height |
|---|---|---|
| Rear-facing harness | 5–40 lb | 19–40 in |
| Forward-facing harness | 30–65 lb | 34.4–49 in |
| Belt-positioning booster (high-back) | 40–100 lb | 43.4–52 in |
$329.99Esgargot · Amazon price as of 2026-11-02 21:52 UTC, subject to change
| Mode | Weight | Height |
|---|---|---|
| Rear-facing harness | 5–40 lb | 19–40 in |
| Forward-facing harness | 30–65 lb | 34.4–49 in |
| Belt-positioning booster (high-back) | 40–100 lb | 43.4–52 in |
$329.99Sea Shadow · Amazon price as of 2026-11-02 21:52 UTC, subject to change
