Kids grow up fast, and the Skyline 2-Stage Belt-Positioning Booster is designed to keep up. The high back provides extra head protection for kids up to 63” tall and can be easily removed for use as a backless booster.

Does the Britax Frontier become backless?

No, it doesn't come off. I don't think it's meant to be a backless booster, but a high back booster/harness booster car seat.

When can a child be in a backless booster?

Here are the general requirements for backless booster seats: Backless booster seat age requirements: From the time kids surpass the weight or height limits allowed by their car seat to about 8 to 12 years of age (depending on the child's size).