In September 1969, AMD moved from its temporary location in Santa Clara to Sunnyvale, California. To immediately secure a customer base, AMD initially became a second source supplier of microchips designed by Fairchild and National Semiconductor. AMD first focused on producing logic chips. The company guaranteed quality control to United States Military Standard, an advantage in the early computer industry since unreliability in microchips was a distinct problem that customers – including computer manufacturers, the telecommunications industry, and instrument manufacturers – wanted to avoid. In November 1969, the company manufactured its first product, the Am9300, a 4-bit MSI shift register, which began selling in 1970. Also in 1970, AMD produced its first proprietary product, the Am2501 logic counter, which was highly successful. Its best-selling product in 1971 was the Am2505, the fastest multiplier available. In 1971, AMD entered the RAM chip market, beginning with the Am3101, a 64-bit bipolar RAM. That year AMD also greatly increased the sales volume of its linear integrated circuits, and by year end the company's total annual sales reached $4.6 million. AMD went public in September 1972. The company was a second source for Intel MOS/LSI circuits by 1973, with products such as Am14/1506 and Am14/1507, dual 100-bit dynamic shift registers. By 1975, AMD was producing 212 products – of which 49 were proprietary, including the Am9102 (a static N-channel 1024-bit RAM) and three low-power Schottky MSI circuits: Am25LS07, Am25LS08, and Am25LS09.