Abstract: An adjuster (100) for use on a pillow, comprising a sheet-like flexible body (200) which is foldable up or down onto itself to provide different thicknesses and has, at or close to a lower edge, a central region (400). The region (400) has a zero or relatively much smaller thickness than that of the body (200) such that opposite sides of the region (400) provide a relatively larger thickness and hence firmer support than the region (400). The region (400) may preferably be a gap (400) formed between a pair of opposed flaps (300) protruding from the body (200).