A shim is a washer or thin strip of material used to align parts, make them fit, or reduce wear. Shims may also be used as spacers to fill gaps between parts subject to wear. On machinery installations (pumps, motors, etc.) the recommended practice requires new shims to be placed under every supporting foot. This guarantees flexibility for adjustments, like a slight raising or lowering of a motor, when parts of the machinery need to be replaced and aligned properly.