A guard rail on the back prevents items from falling off when the shelf is moved. The refrigerator should have two industry seals. Underwriters laboratories indicates that it meets safety standards. The Association of Home Appliance Manufactures seal attests to the accuracy of capacity and net shelf area. Look through the instruction book with details for operating and caring for the refrigerator, before you consider buying.
Warranty varies with the manufacturer.
It may go beyond the standard one year on the refrigerator plus four additional years on the refrigerator mechanism. Buy a recognized brand from a dealer who services what he sells. Send in the warranty card to the manufacturer. Read the instruction book. Keep it handy and refer to it often.