Abstract: A foam part of an expandable plastic, in particular polyurethane or the like, for use as a cushioning element in a seating surface. The foam material has essentially homogeneous material properties, at least in the core of the foam part, and at least one insert with flat X-Y expansion is foamed into the core of the foam part essentially parallel to the seating surface. The insert is at least partially foamable by the expandable plastic, and has a specific elasticity in the X-direction and/or Y-direction.