# Chicco KeyFit 35 Infant Car Seat vs CYBEX Sirona S with SensorSafe Convertible Car Seat: specs and price compared

A sourced, side-by-side comparison of the Chicco KeyFit 35 Infant Car Seat (Chicco) and CYBEX Sirona S with SensorSafe Convertible Car Seat (CYBEX) among car seats. Chicco KeyFit 35 Infant Car Seat is the cheaper of the two at $249.99.

## Side by side

| Spec | Chicco KeyFit 35 Infant Car Seat | CYBEX Sirona S with SensorSafe Convertible Car Seat |
| --- | --- | --- |
| US price | $249.99 | $349.99 |
| Brand | Chicco | CYBEX |
| Released | 2020 | — |
| Type | infant | convertible |
| Min weight (lb) | 4 | 4 |
| Max weight (lb) | 35 | 65 |
| Height limit (in) | 32 in | 49 in |
| Install | both | both |
| Steel frame | Yes | — |
| Expiration years | 6 | 10 |

## Key differences

- Type: Chicco KeyFit 35 Infant Car Seat infant vs CYBEX Sirona S with SensorSafe Convertible Car Seat convertible
- Max weight (lb): Chicco KeyFit 35 Infant Car Seat 35 vs CYBEX Sirona S with SensorSafe Convertible Car Seat 65
- Height limit (in): Chicco KeyFit 35 Infant Car Seat 32 in vs CYBEX Sirona S with SensorSafe Convertible Car Seat 49 in
- Expiration years: Chicco KeyFit 35 Infant Car Seat 6 vs CYBEX Sirona S with SensorSafe Convertible Car Seat 10

## What reviewers say

**Chicco KeyFit 35 Infant Car Seat** — One whitelisted hands-on tester (Reviewed/USA Today) reviewed this exact model, recommending the KeyFit 35 as an easy-to-install, comfortable, washable, budget-friendly infant seat while flagging it as bulky/awkward to carry and unattractive. No lab-measured data exists: Reviewed explicitly states it does not crash-test and relies on NHTSA safety ratings. (1 sourced review.)

## Sources

- Chicco KeyFit 35 Infant Car Seat: https://www.chiccousa.com/shop-our-products/car-seats/infant/keyfit-35-infant-car-seat/79625.html (chiccousa.com, verified 2026-06-19)
- CYBEX Sirona S with SensorSafe Convertible Car Seat: https://www.cybex-online.com/en/us/p/cs-go-sirona-s-sensorsafe-3.html (cybex-online.com, verified 2026-06-19)

Canonical: https://frontdeskreview.com/gear/car-seats/chicco-keyfit-35-vs-cybex-sirona-s/
Cite: Per The Front Desk Review, Chicco KeyFit 35 Infant Car Seat ($249.99) vs CYBEX Sirona S with SensorSafe Convertible Car Seat ($349.99) — sourced spec-by-spec comparison at https://frontdeskreview.com/gear/car-seats/chicco-keyfit-35-vs-cybex-sirona-s/
License: CC BY 4.0.