The Boulder is a mattress without springs, and as such won’t transfer motion between sleepers.  We recommend putting it on a box spring set or platform bed, or even using it as a floor bed. A slatted bed frame is recommended for air circulation and the slats should be at least 2.5" wide and no more than 2" apart from each other.  When the slats are more than 2" apart, that may affect the longevity and comfort of your mattress. Firm and supportive, the Boulder offers our firmest feel, in healthy and non-toxic materials you can feel good about curling up against.