side underneath the u201c d u201d ring the u201c d u201d rings will allow a partially loaded truck to carry tall stacks of bins against the walls fig9 the preferred embodiment of the stackable open front grocery and goods bin with air cushion mobility is injection molded plastic the mold release angle is inclined approximately 20 degrees up and to the front fig4 the bottom mold release angle is inclined approximately 20 degrees down and to the rear the sides of the bin are molded with an 8 to 10 degree release angle and the top edge of each side is turned outward and curled downward so form an approximately 2 cm wide curled ledge than can be used for picking up and carrying the bin by hand fig6 the top back edge of the bin is also turned outward to form about a 2 cm wide ledge than can be used for picking up and carrying the bin by hand but the void under the rear curl is cast solid except for pits about 1 cm wide and 2 cm apart on the underside of this ledge to engage the sprockets of the bin 39 s associated conveyer machinery fig6 fig7 the top half of the back of the bin is vertical but the bottom half of the back of the bin is tilted inward with approximately a 10 degree angle so that a plumb line hung over the top edge will exactly touch the radius of curvature where the back of the bin joins the bottom of the bin fig4 fig6 it is because of this that the mold release angle must be approximately 20 degrees tilted toward the front and the bottom front of.