The Pentagon (ru: Пентагон) home computer was a clone of the British-made Sinclair ZX Spectrum 128.

It was manufactured by amateurs in the former Soviet Union, following freely distributable documentation.

Its PCB was copied all over the ex-USSR in 1991-1996, which made it a widespread ZX Spectrum clone.

[1] Many simple devices (upgrades) were invented to connect to the Pentagon with some soldering.

[2] The Pentagon 1024SL v2.3 included most of the upgrades of the standard Spectrum architecture, including 1024 KB RAM, Beta 128 Disk Interface and ZX-BUS slots (especially for IDE and General Sound cards).