# Booster car seats and existing vehicle headrests

Which booster car seats work with a vehicle that already has a headrest?

PEG / Peg Perego Primo Viaggio Flex 120: It is one of the tallest boosters on the market; the highest belt guide is 22 inches, with a 63\-inch height limit and 120\-pound weight limit, and no vehicle head restraint is needed\. Britax Grow With You Harness\-2\-Booster: It changes from a forward\-facing 5\-point harness car seat into a high\-back booster\.

### 1. [PEG / Peg Perego Primo Viaggio Flex 120](/products/ucp/strolleria-com/3782284247114) (sold by strolleria\.com)

It is one of the tallest boosters on the market; the highest belt guide is 22 inches, with a 63\-inch height limit and 120\-pound weight limit, and no vehicle head restraint is needed\.

- Vehicle headrest: It is one of the tallest boosters on the market; the highest belt guide is 22 inches, with a 63\-inch height limit and 120\-pound weight limit, and no vehicle head restraint is needed\. (blog) <https://thecarcrashdetective.com/peg-perego-viaggio-flex-120-review/>
- Seat type: This is a booster seat, not a car seat: the child sits on it and uses the vehicle's seat belt as the restraint\. (manual) <https://www.pegperego.com/media/catalog/product/download/FIUS2301I235-FLEX-120-USA.pdf>

### 2. [Britax Grow With You Harness\-2\-Booster](/products/ucp/anbbaby-com/8799029788958) (sold by anbbaby\.com)

It changes from a forward\-facing 5\-point harness car seat into a high\-back booster\.

- Vehicle headrest: -
- Seat type: It changes from a forward\-facing 5\-point harness car seat into a high\-back booster\. (guide) <https://us.britax.com/shop/car-seats/grow-with-you-harness-2-booster-car-seat>

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Written 2026-10-25T01:22:47.805Z.

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