The type of lifejacket you’re describing is a hybrid lifejacket: it combines foam and an inflatable chamber, and it comes in child, youth, and adult sizes.

Quick Scoop

Hybrid lifejackets are designed to give you the steady buoyancy of foam with the extra lift of inflation when needed.

How it fits the clues

  • Made from foam and inflatables.
  • Available in child, youth, and adult sizes.
  • It’s a wearable PFD style, not just a throw cushion.

Simple distinction

  • Foam / inherently buoyant : mostly foam, available in many sizes.
  • Inflatable : uses a gas cylinder, usually adult-only.
  • Hybrid : foam plus inflatable chamber, available in child, youth, and adult sizes.

In plain terms, the answer is hybrid lifejacket.

Information gathered from public forums or data available on the internet and portrayed here.