The ZX Spectrum is an 8-bit home computer developed and marketed by Sinclair Research. It was first released in the United Kingdom on 23 April 1982, and around the world in the following years, most notably in Europe, the United States, and Eastern Bloc countries. The machine was the creation of English entrepreneur and inventor Sir Clive Sinclair. Referred to during development as both the ZX81 Colour and the ZX82, the ZX Spectrum was designed by a small team in Cambridge. It was designed to be small, simple, and most importantly inexpensive, with as few components as possible. The addendum "Spectrum" was chosen to highlight the machine's colour display, which differed from the black-and-white display of its predecessor, the ZX81. Its distinctive case, rainbow motif and rubber keyboard were designed by Rick Dickinson. Video output is transmitted to a television set rather than a dedicated monitor, while software is loaded and saved onto compact audio cassettes. It was initially distributed through mail order, but after severe backlogs the machine was sold through High Street chains in the United Kingdom. It was released in the United States as the Timex Sinclair 2068 in 1983, and in some parts of Europe as the Timex Computer 2048. Ultimately the Spectrum was released as six different models, ranging from the entry level with 16 KB RAM released in 1982 to the ZX Spectrum +3 with 128 KB RAM and built-in floppy disk drive in 1987, which was developed under the new Amstrad ownership. Throughout its life, the machine primarily competed with the Commodore 64, BBC Micro, Dragon 32, and the Amstrad CPC range. Not counting unofficial clones, the machine sold over 5 million units worldwide. Over 24,000 different software products were released for the ZX Spectrum. The ZX Spectrum played a pivotal role in the early history of personal computing and video gaming, leaving an enduring legacy that influenced generations. Its introduction led to a boom in companies producing software and hardware, the effects of which are still seen. It was among the first home computers aimed at a mainstream audience, with some crediting it as being responsible for launching the British information technology industry. It remains Britain's best-selling computer. The machine was officially discontinued in 1992.