Here are some rather old HO gauge Aristocraft 551 Tunnel Retaining Wall Set model kits.  There are 5 of them, still in VERY old cellophane rack packages (*which are disintegrating, although the contents does appear to be fine).  Found all in 3 bags from Mandel Brothers in Chicago, Illinois.  Not sure how old exactly these are, but the Mandel Brothers bag does NOT have any ZIP code yet!  These have sat in storage literally for decades, never used, but I listed them as used because the packages are falling apart, and I do not know if they are all complete.  There are definitely enough parts to make several of these, anyway (each kit makes one tunnel retaining wall).  The rack cards state that these were made in Germany FOR Aristocraft.  Perhaps someone will want them to build for a layout, or perhaps as a collectible.  Photos show front and back of all of them, plus a closeup of the header card, and a shot of the Mandel Brothers bag I found them in, all with a yardstick in the shots for size reference.  Could only find a single kit (in a box, not a bag) on EBay, and that guy wanted just shy of $15, so all of these for $25 should be quite a bargain for someone out there.  Winner charged only actual USPS Ground Advantage or Priority Shipping cost.