The MITS Altair 8800 was a microcomputer design from 1975 based on the Intel 8080 CPU and sold by mail order through advertisements in Popular Electronics, Radio-Electronics and other hobbyist magazines. Both kits and fully assembled machines were available (the serial number of a kit ends with a K). The designers intended to sell only a few hundred to hobbyists, and were surprised when they sold thousands in the first month. Today the Altair is widely recognized as the spark that led to the microcomputer revolution of the next few years: The computer bus designed for the Altair was to become a de facto standard in the form of the S-100 bus, and the first programming language for the machine was Microsoft's founding product, Altair BASIC.