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Image: Safety 1st, from safety1st.com. Colors may differ from the seat you buy. See it on safety1st.com
An all-in-one car seat with 4 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; backless booster 40 to 100 lb, 43.4 to 57 in.
$199.99on safety1st.com, as of 2026-10-07 05:49 UTC. Prices change.
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The Safety 1st SlimRide 4-in-1 (CC418) is a four-mode seat. Its manual lists rear-facing 5 to 40 lb and 19 to 40 in., forward-facing 30 to 65 lb and 34.4 to 49 in., high-back booster 40 to 100 lb and 43.4 to 52 in., and backless booster 40 to 100 lb and 43.4 to 57 in. Expiry: 10 years.
It suits a family that wants a seat running from newborn to backless booster and does not need a magnetic chest clip. The trade-off is in the details: the manual's parts page says the SlimRide version has no cup holder snack lid and no magnetic chest clip, and forward-facing the lower anchors stop at a 45 lb child. The EverSlim 4-in-1 lists the same harness limits on its page and adds the SecureTech chest clip.
A research summary of Safety 1st’s published specifications and manual, read . Not a hands-on test or a crash-safety rating.
This seat covers 4 stages, and a child has to meet every limit of the stage they are in. Safety 1st 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 | — |
| Backless booster | 40 to 100 lb | 43.4 to 57 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.
Safety 1st does not publish a width for this seat, so measure your back seat and compare it with the seat in a store before buying.
Grey All Day, Royal Flush, Black Beauty.
When they differ, follow the manual and the labels on your seat.
The manual (an image-only PDF, read here by text recognition) says the seat has 5 positions, with a small window on each side showing which is set. Position 1 must not be used rear-facing. For a child 5 to 30 lb and 19 to 34.3 in., the bottom level line must be parallel with the ground using Positions 5 to 2. For 30 to 40 lb and 34.4 to 40 in., and only if the child can sit up unassisted, the top level line applies using Positions 4 to 2. Rear-facing, the tether stays stored, and the LATCH belt and vehicle belt are never used together.
Source: SlimRide 4-in-1 manual (PDF)
Forward-facing with the harness covers 30 to 65 lb and 34.4 to 49 in. The manual says not to use the lower anchors (LATCH) when restraining a child over 45 lb (20 kg); above that, install with the vehicle belt. When the vehicle has a tether anchor, the tether should be attached and tightened in forward-facing harness mode. A seat that moves more than 1 in. at the belt path needs a tighter install, a reinstall or another seating position.
Source: SlimRide 4-in-1 manual (PDF)
For booster use, the head pillow, body pillow and harness covers come off and the harness is stored. The backless booster separates from the main seat with the release levers under the seat pad. In backless mode, the lap belt runs through the booster belt path under both armrests, and the shoulder belt goes under the armrest on the buckle side and over the armrest on the other side. The child's ears must not be above the top of the vehicle seat back or headrest. In both booster modes, the manual says not to use the seat if the child's head is less than 5 in. below the vehicle roof.
Source: SlimRide 4-in-1 manual (PDF)
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 lists rear-facing 5 to 40 lb and 19 to 40 in., forward-facing 30 to 65 lb and 34.4 to 49 in., backed booster 40 to 100 lb and 43.4 to 52 in., and backless booster 40 to 100 lb and 43.4 to 57 in.
Yes, with the internal harness. The manual says it is not certified for aircraft use as a booster, because aircraft seats have no shoulder belts, and says to use it only on forward-facing aircraft seats.
The manual says not to use it more than 10 years after the date of manufacture, shown on labels on the bottom of the main shell and of the backless booster.
Machine wash it separately in cold water on a gentle cycle with the harness covers closed, with no bleach. Tumble dry separately for 10 to 12 minutes on low heat and remove it right away.
The EverSlim page lists the same rear-facing (5 to 40 lb, 19 to 40 in.) and forward-facing (30 to 65 lb, 34.4 to 49 in.) limits, a 5-position recline base, a 10-position headrest, and a SecureTech chest clip with a red-to-green indicator.
Safety 1st EverSlim 4-in-1 product page (opens in a new tab)
No. The manual's parts page says the SlimRide version has no cup holder snack lid and no magnetic chest clip.
Answers refer to the model and manual version on this page. Check the instructions supplied with your seat.
Other all-in-one seats whose published weight and height limits overlap the SlimRide 4-in-1 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 |
$129.99Deep Sea 2 · Amazon price as of 2026-11-02 00:52 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 |
$139.99Price on safety1st.com as of 2026-10-07 05:49 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 |
| Backless booster | 40–100 lb | 43.4–57 in |
$259.99Vintage Mickey Mouse 2 · Amazon price as of 2026-11-02 00:52 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 |
$239.98Mickey Sprinkle · Amazon price as of 2026-11-02 00:52 UTC, subject to change
