The PCW was the Amstrad computer in production for the longest time(1985 - 1996). And the Amstrad computer with the most model revisions (Starting with the PCW8256 and ending with the PcW16). All models was based on the Z80 CPU.
The series consists of PCW 8256 and PCW 8512 (introduced in 1985), PCW 9512 (introduced in 1987), PCW 9256 and PCW 9512+ (introduced in 1991), PCW 10 PcW10 and PcW16 (introduced in 1995).
8 million units sold worldwide (over 200,000 in UK) [https://www.retroisle.com/amstrad/pcw/general.php Source].