Fursat - CMOS Battery - Motherboards include a small separate block of memory made from CMOS RAM chips which are kept alive by a battery (known as a CMOS battery) even when
100pcs D43256AC-10L 32,768 X 8BIT STATIC CMOS RAM NEC Microprocessor IC PDIP-28 | eBay
Major Brands BS62LV4006PIP-55 Very Low Power CMOS Static RAM, 512K x 8 Organization, PDIP-32: Electronic Components: Amazon.com: Industrial & Scientific