Abstract: An adapter for increasing the frictional force generated by a spacer interposed between a pair of items. The spacer defining a pair of opposed load bearing surfaces and a pair of spacing surfaces. The adapter includes a relatively flat plate defining a pair of plate surfaces, a pair of opposed contacting edges and a pair of spacing edges. A fixing component is provided for fixing the plate to one of the spacing surfaces of the spacer. A set of friction increasing teeth extend from at least one of the contacting edges for increasing the friction coefficient of the contacting edge with an item. The plate is configured and sized so that the friction enhancing teeth protrude from one of the load bearing surfaces when the plate is mounted on the spacer. In one embodiment, the adapter also includes an auxiliary friction enhancing segment for enhancing the friction between the adapter and contacting items.