Rackable collapsible stackable unit

A rackable, collapsible, and stackable unit comprising:

• two pairs of adjacent and opposite upright corner posts being foldable inwardly and downwardly;
• a pair of opposite upright center posts being foldable inwardly and downwardly and centrally located between the pairs of adjacent upright corner posts;
• two side bars, each side bar connecting the pair of opposite upright corner posts;
• two pairs of first end bars, each pair of first end bars connected between the pair of adjacent upright corner posts and one of the center posts;
• two pairs of second end bars, each pair of second end bars connected between the pair of adjacent upright corner posts and one of the center posts, positioned at a point lower than the pair of first end bars on the corner posts;
• at least two first core holders located on a first one of the two pairs of first end bars for retaining a core;
• at least two second core holders, each second core holder connected to an opposite end of at least a second one of the at least two pairs of first end bars on an upper side of the end bars and shaped so as to receive one end of a core;
• a plurality of hinges, one connected at each joint between each corner post and the side bars and each joint between the center post and the second end bars;
• and
• at least four hinged support braces, each one pivotally and diagonally connected between one of the corner posts and one of the side bars to hold the corner posts in an upright position when the unit is opened and which, in combination with the hinges, makes it possible to fold the corner posts inwardly and downwardly so as to lie substantially flat against the side bars.