Abstract: The invention provides a combination of a post and an end connector for use in a rack system to support shelves and the like. The posts have first and second side ribs extending longitudinally and center portions extend between the side ribs. Each center portion defines longitudinally spaced slots and the side ribs are disposed symmetrically to either side of the center portions. The end connector has a channel shape adapted to fit snugly over a side rib of one of the posts. Coupling elements extend from the channel shape and each has a cantilever portion and a downward projection dependent from an end of the cantilever portion. The projection defines a rearward face inclined downwardly and rearwardly for engagement with a rearward side of the center portion of the post after engaging the coupling element in the post.