A high density nesting packaging element is a preformed, rigid U-shaped member. The U-shaped member has a base wall and upstanding opposing side walls, in which the intersection of the base and side walls is rigid. The base wall has a thickness and a narrow slit is formed in the base wall, extending longitudinally along the base wall. The slit is formed from an inner surface of the wall into the thickness of the base wall. The base wall is foldable along the slit so as to form a generally W-shaped configuration cross-section. When folded into the W-shaped configuration, the members are nestable with each other. When the member is unfolded to the U-shaped cross-section, the opposing surfaces formed by the slit abut one another to maintain the member in the U-shaped configuration.