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Cybex Sirona S fit guide
A 360° rotating convertible that is unusually narrow for a swivel seat — the rare rotating pick that can still work in tighter back seats. Here's exactly which children it fits, how NHTSA rated it, and which cars it fits — including three-across.
Which children it fits
| Mode | Weight | Height | LATCH limit |
|---|---|---|---|
| Rear-facing | 4 lb – 50 lb | up to 49" | up to 35 lb on lower anchors |
| Forward-facing harness | 22 lb – 65 lb | up to 49" | up to 35 lb on lower anchors |
Weight/height limits are the seat's NHTSA-published values. Beyond the LATCH limit, install with the vehicle seat belt instead of the lower anchors. Always follow the labels on your seat and the vehicle manual.
NHTSA Ease-of-Use detail
NHTSA's Ease-of-Use rating measures how easy a seat is to install and use correctly — the single biggest factor in real-world safety, since most seats are installed wrong. It is not a crash-test score; NHTSA does not crash-rate individual car seats.
Which cars the Sirona S fits three across
At 17" wide, three Sirona Ss should fit across the back of these vehicles we track (test-fit to confirm):
Will it fit your exact car?
Check the Sirona S against a specific vehicle — single position and three-across:
Common questions
What are the weight and height limits of the Cybex Sirona S?
Rear-facing: 4 lb–50 lb and up to 49" tall; Forward-facing harness: 22 lb–65 lb and up to 49" tall. These are the manufacturer's NHTSA-published limits — always defer to the label on your seat.
How is the Cybex Sirona S rated by NHTSA?
NHTSA gave the Cybex Sirona S an Ease-of-Use rating of 5/5 stars, including 5/5 for vehicle-installation features. Ease-of-Use measures how easy the seat is to install and use correctly — not crash performance, which NHTSA does not rate for individual seats.
Can the Cybex Sirona S fit three across?
The Cybex Sirona S is about 17" wide. Three should fit across the back seat of 6 of the vehicles we track, including the 2015–2024 Subaru Outback, 2020–2024 Toyota Highlander, 2016–2022 Honda Pilot.
Sources: ratings, modes & recalls — NHTSA (pulled 2026-06-17); external width — Cybex published spec (~17 in at base; approximate). Informational only — built from NHTSA public car-seat ratings and published seat/vehicle dimensions. This is not a safety certification and not a substitute for the seat and vehicle manuals. Always confirm the fit and install yourself before every trip.