This was the SCELBI 8-H, the first computer kit based around a microprocessor, in this case the Intel 8008.

first computer kit of

RCA connector (Wikipedia) The RCA connector is a type of electrical connector commonly used to carry audio and video signals. The name RCA derives from the company Radio Corporation of America, which introduced the design in the 1930s. The connector’s male plug and female jack are called RCA plug and RCA jack.

From ACS to Altair: The Rise of the Hobby Computer (technichistory.com) A certain pattern of technological development recurred many times in the decades around the turn of the twentieth century: a scattered hobby community, tinkering with a new idea, develops it to the point where those hobbyists can sell it as a product. This sets off a frenzy of small entrepreneurial firms, competing to sell to other hobbyists and early adopters. Finally, a handful of firms grow to the point where they can drive down costs through economies of scale and put their smaller competitors out of business. Bicycles, automobiles, airplanes, and radio broadcasting all developed more or less in this way.