Resilient unit

A method of producing a resilient unit suitable for providing comfort, convenience, support or protection, the unit having an upper surface and a lower surface, wherein the upper surface is arranged in use to support a load, the method comprising:

• arranging a plurality of coil springs in an array, each spring being frusto-conical in shape and comprising a plurality of coils that decreases in diameter from a first axial end to a second axial end of the spring, and being substantially encased in one of a plurality of individual pockets, and the unit being compressible in an axial direction of the springs, the axial direction of the springs being substantially perpendicular to a plane of the array;
• and
• forming the plurality of pockets by joining axially spaced layers of material together at least at locations between the plurality of coil springs, and wherein, the layers of material are joined between the at least two springs at a position that is closer to, but not at, the first axial end of the spring, such that the position at which the two layers are joined is a first distance (d) from the upper surface of the resilient unit and a second distance (D) from the bottom surface of the resilient unit that is greater than the first distance, wherein a ratio of the first distance relative to a total distance (d+D) between the upper surface and the lower surface (d/d+D) is in the range between 0.25 and 0.3 inclusively,
• wherein the first axial ends of the springs are located towards the upper surface of the unit, and wherein the unit is flexible in at least one lateral direction that is generally perpendicular to the axial direction of the springs and so that the unit is at least partially compressible in at least one direction transverse to the axial direction of the springs.