Caster connector part for old Elfa cart (from at least early 90s). The original plastic piece broke, and the only way to purchase a replacement part is to buy an entire set of 4 casters. I measured the original broken part and modeled in AutoCAD. I made a few test pieces first to get sizing right, and all connections fit snugly and should stay in place if the cart is lifted.

Note: The modern Elfa caster connectors appear to have a slightly different design. This may or may not work with newer Elfa drawer units.