An airframe waterbed mattress doesn’t require any other wooden frame, although it can be placed in one. It can support its own. Think of it as similar to an air bed except that it has water inside. An air chamber surrounds and protects its perimeters.

It is lighter than standard waterbed mattresses.  As such, it may also be an alternative to air beds during camping trips or for weekend guests.

As with air beds, water level may be adjusted for comfort and into four different types: free flow, semi-waveless, waveless, and ultra-waveless.

Via Specialty Bedding