Owners of items that are rare, collectible, or of historical value bring them for appraisal by a series of four dealers in separate rooms. Each dealer offers a cash price, which the owner can either accept or reject in favor of moving on to the next room. However, once an offer is rejected, the owner cannot return to it after hearing other offers. If the owner rejects all four offers, the item is immediately sold at auction to see if it can bring a better price than the dealers were ready to give.
—Alan Back